【正确答案】 B

【答案解析】[听力原文]
Today I"d like to discuss the first non-instance of strange evolutionary strategy. This phenomenon occurs in a flowering plant called the scarlet jilia. The scarlet jilia depends on hummingbirds and moths for pollination. And the blossoms seem to change their color for each of these pollinators. On fern mountains near Flagstaff, Arizona where these flowers grow, hummingbirds arrive in mid-July to drink nectar from the scarlet jilia. In July, the flowers are bright red, which is attractive to the hummingbirds. By late August, however, the hummingbirds leave the area for a warmer climate. As the weather cools, the color of the plant blossoms changes to white, a color that attracts a particular moth species, the night-flying hawk moths. Apparently, this kind of moths can see these white blossoms easily at night. These moths continue to pollinate the flowers until well into September. The scarlet jilia demonstrates at an unusual way in which the plant lures pollinators to continue its life cycle.

What"s the main topic of the talk?

[解析] 从“I"d like to discuss the first non-instance of strange evolutionary strategy”可推知谈一个非实例的进化方式。non-instance非实例的。

【正确答案】 C

【答案解析】[听力原文]
Why is the scarlet jilia plant considered to be unusual?

[解析] “And the blossoms seem to change their color for each of these pollinators. ”(对于每个传粉者，花好像是变化颜色的)。

【正确答案】 A

【答案解析】[听力原文]
Why do the hummingbirds leave fern mountains?

[解析] 从“By late August, however, the hummingbirds leave the area for a warmer climate. ”可推知蜂鸟离开这个地方去找暖和的去处。

【正确答案】 D

【答案解析】[听力原文]
When is the scarlet jilia plant pollinated?

[解析] 从“These moths continue to pollinate (授粉) the flowers until well into September”可推知至少直到九月，这些飞蛾继续授粉。

【正确答案】 D

【答案解析】[听力原文]
According to the speaker, in what way are white blossoms attractive to moths?

[解析] 从“this kind of moths can see these white blossoms easily at night. ”可推知这种类型的飞蛾在夜晚能够容易地看到这些花。