1. What is the lecture mainly about?
a. The growth rates of plants in different geographical regions
b. Different ways that plants have adapted to desert environments
c. The different mechanisms that plant roots use to absorb water
d. Different kinds of succulent plants
解析：(从第23秒开始，原文重现：So, with desert plants, there are basically three different adaptive strategies.)
2. What are two features of succulent plants that help them survive in deserts?
Click on 2 answers.
a. Succulent plants store water in their leaves and stems.
b. Succulent plants become dormant until the next rainfall.
c. Succulent plants have short stems.
d. Succulent plants have few leaves.
答案： A, D
破题关键词汇： features, succulent plants
解析：(从第1分25秒开始，原文重现：Succulent plants can store water in their leaves, in their stems, or in their roots.
从第1分50秒开始，原文重现：And that means that most succulent plants have few, if any, leaves.)
3. Why does the professor mention bears?
a.To remind students of information from a previous lecture
b.To point out a feature common to all desert plants
c.To reinforce a point about drought-tolerant plants
d.To help students understand the concept of adaptation
解析：(从第1分56秒开始，原文重现：Now, besides succulent plants, there're also drought-tolerant plants. Drought-tolerant plants are like bears in a way. You know how bears mostly sleep through the winter. They can survive without eating because their metabolism slows down. Well, drought-tolerant plants also go into a dormant state when resources, in their case, water, run short. A drought-tolerant plant can actually dry out without dying.)
4. What is one ability that drought-tolerant plants have that succulent plants do not have?
a. a. The ability to absorb water from dry soil
b. The ability to absorb water through their leaves
c. The ability to prevent moisture from being lost through their leaves
d. The ability to shed leaves
解析：(从第2分45秒开始，原文重现：Drought tolerant plants can even absorb water from relatively dry soil because of their deep roots in contrast to succulent plants.)
5. Why can annual plants grow in a desert even after a year of no rainfall?
a. Annual plants have an extensive root system that can absorb water from far away.
b. Annual plants produce seeds all year long.
c. Seeds of annual plants can store water for a long time.
d. Seeds of annual plants can survive in the ground for a long time without water.
解析：(从第3分29秒开始，原文重现：But they have a mechanism to prevent one year of low rainfall from wiping them out.)
6. Why does the professor say this :
a. To correct a previous statement
b. To acknowledge a potentially surprising fact
c. To anticipate the types of questions that students might have about the topic
d. To make sure that students are paying attention
破题关键词汇：There ARE plants that do this.
解析：(从第2分59秒开始，原文重现：Yes! There ARE plants that do this.)