【正确答案】The lecture is about two methods insects employ to breathe underwater.
One way is for the insect underwater to have part of its body out of the water. For example, the water scorpion has a tail-like tube. The tube sticks above the water's surface and the insect breathes through it.
The other method is for the insect to carry air underwater with it. For instance, the diving beetle's wings trap air above the water and form bubbles. It then breathes from the bubbles when it goes below the surface.

【答案解析】[听力原文]
W: The way insects adapt to the most unlikely environments is fascinating. Everyone knows that fish breathe underwater, right? However, it's not only fish that can breathe underwater. Some insect species do, too! There are two ways different kinds of insects manage to breathe underwater.
The first way is for the insect underwater to go on breathing the air above water. Take the water scorpion as an example. The creature is actually an insect that looks a bit like a real scorpion. This little bug has a long tail, like a scorpion. Only the tail is actually a tube. When the insect is underwater, the end of the tail is still above the water. The insect then goes on breathing through this tube. That's right, just like people using a snorkel tube when they swim a little way underwater.
The other way insects breathe underwater is for them to go all the way under, but to take air with them. For instance, there's an insect called "diving beetle." I understand it's found mostly in Europe, especially England. This insect catches air with its outer wings while it is above water. Then, when it goes under the water, it carries this air with it as bubbles. These bubbles then give it a supply of air to breathe from. Again this is like a human diver, carrying a bottle of air with him when he dives.

Alternative Wording(替换表达)
Synonyms (a)underwater—submerged
(b)stick—extend
(C)go below the surface—dive, submerge
Paraphrases 1. One method is for the insect to be only partially submerged.
2. The other method calls for the insect to transport its own air supply when it dives.