It's time to say goodbye to summertime because today is officially the first day of fall, also called autumnal equinox. During the vernal and autumnal equinoxes, the sun is directly over the equator, so day and night are considered to be the same length. If you reside in the northern hemisphere, you know it is the start of fall, but folks down south of the equator, this equinox is actually the start of spring. This is not to be confused with a solstice though. Those are in the summer and the winter and represent the longest and shortest days of the year respectively. So when it comes to fall, you might be thinking about colder temperatures, pumpkin spice lattes, some football or fallen leaves. And speaking of leaves, let's take a minute to learn why they actually change color in the fall.

I want you think about leaves on a tree as essentially many solar panels. What they're able to do is fascinating. They are taking the sunlight in and through a process known as photosynthesis. They're able to transfer the sun's energy and create a chemical known as chlorophyll. Now, chlorophyll is key because it gives the leaves its green colors during the long summer months. But beneath the surface, the leaves actually always have the reds, the oranges, the yellows in place while chlorophyll is there, it's there and it's green. While it's taken away in the shorter days and shorter months of the autumn, now you're releasing some of the true colors back to the surface. Of course, weather can play a role in this as well, especially in the vibrancy of it. When you have plenty of rainfall in the growing season or in the spring season, you're able to get plenty of good colors in early September, October and November. If you have extreme heat, extreme drought in place, maybe a freeze early snowstorm or even strong winds, certainly that can do damage. The leaves will not be there for you to see them in peak foliage. So hopefully, you get a chance to get out there this year and enjoy the fall colors.

1. autumnal equinox 秋分

2. vernal adj. (formal, or literary) connected with the season of spring 春季的。例如：the vernal equinox春分

3. reside v. (formal) to live in a particular place 居住在；定居于。例如：He returned to Britain in 1939, having resided abroad for many years. 他在国外居住多年以后，于1939年回到了英国。

4. solstice n.（夏或冬）至。例如：the summer/winter solstice夏至；冬至

5. lattes n. 拿铁（一种加热奶的浓咖啡）

6. photosynthesis n. (biology 生) the process by which green plants turn carbon dioxide and water into food using energy obtained from light from the sun 光合作用

7. chlorophyll n. the green substance in plants that absorbs light from the sun to help them grow 叶绿素

8. vibrancy n. 活跃

9. foliage n. the leaves of a tree or plant; leaves and branches together （植物的）叶；枝叶。例如：dense green foliage茂密的绿叶

It's time to say goodbye to summertime because today is officially the first day of (Q1) _________, also called autumnal equinox. During the vernal and autumnal equinoxes, the sun is directly over the equator, so day and night are considered to be the same length. If you reside in the northern (Q2) _____________, you know it is the start of fall, but folks down south of the equator, this equinox is actually the start of spring. This is not to be confused with a solstice though. Those are in the summer and the winter and represent the longest and shortest days of the year (Q3) _______________. So when it comes to fall, you might be thinking about colder temperatures, pumpkin spice lattes, some football or (Q4) _________________. And speaking of leaves, let's take a minute to learn why they actually change color in the fall.

I want you think about leaves on a tree as essentially many (Q5) _______________. What they're able to do is fascinating. They are taking the sunlight in and through a process known as photosynthesis. They're able to (Q6) _________________ the sun's energy and create a chemical known as chlorophyll. Now, chlorophyll is key because it gives the leaves its (Q7) ____________________ during the long summer months. But beneath the surface, the leaves actually always have the reds, the oranges, the yellows in place while chlorophyll is there, it's there and it's green. While it's taken away in the shorter days and shorter months of the autumn, now you're releasing some of the true colors back to the surface. Of course, (Q8) _______________ can play a role in this as well, especially in the vibrancy of it. When you have plenty of (Q9) _______________in the growing season or in the spring season, you're able to get plenty of good colors in early September, October and November. If you have extreme heat, extreme drought in place, maybe a freeze early (Q10) __________________ or even strong winds, certainly that can do damage. The leaves will not be there for you to see them in peak foliage. So hopefully, you get a chance to get out there this year and enjoy the fall colors.

It's time to say goodbye to summertime because today is officially the first day of (Q1) fall, also called autumnal equinox. During the vernal and autumnal equinoxes, the sun is directly over the equator, so day and night are considered to be the same length. If you reside in the northern (Q2) hemisphere, you know it is the start of fall, but folks down south of the equator, this equinox is actually the start of spring. This is not to be confused with a solstice though. Those are in the summer and the winter and represent the longest and shortest days of the year (Q3) respectively. So when it comes to fall, you might be thinking about colder temperatures, pumpkin spice lattes, some football or (Q4) fallen leaves. And speaking of leaves, let's take a minute to learn why they actually change color in the fall.

I want you think about leaves on a tree as essentially many (Q5) solar panels. What they're able to do is fascinating. They are taking the sunlight in and through a process known as photosynthesis. They're able to (Q6) transfer the sun's energy and create a chemical known as chlorophyll. Now, chlorophyll is key because it gives the leaves its (Q7) green colors during the long summer months. But beneath the surface, the leaves actually always have the reds, the oranges, the yellows in place while chlorophyll is there, it's there and it's green. While it's taken away in the shorter days and shorter months of the autumn, now you're releasing some of the true colors back to the surface. Of course, (Q8) weather can play a role in this as well, especially in the vibrancy of it. When you have plenty of (Q9) rainfall in the growing season or in the spring season, you're able to get plenty of good colors in early September, October and November. If you have extreme heat, extreme drought in place, maybe a freeze early (Q10) snowstorm or even strong winds, certainly that can do damage. The leaves will not be there for you to see them in peak foliage. So hopefully, you get a chance to get out there this year and enjoy the fall colors.