【答案解析】The lecture talks about the definition of carnivorous plants and introduces two types of preying methods: active and passive. Active preying method is applied by plants like the Venus fly. They have two oval lobes on the end of their leaves, where there are three trigger hairs. The lobes wrap the insect tightly when it touches the trigger hairs. Then, some digestive enzymes will be released to decompose the insect's body. The pitcher plant is an excellent example of the passive trap. The plant has tall leaves, and when insects enter the top of a leaf, the slippery plant that points downward would direct the insect further and further into the center. Eventually, the insect will fall into the water at the bottom and drown to death. [听力原文] W: Carnivorous plants generally grow in areas where the soil lacks nutrients. These plants have adapted themselves to trap insects as food source in order to supplement what they need to grow. Carnivorous plants can be divided into three specific groups. There are plants with passive traps, active traps or those that have both. Plants that have active traps include the most famous carnivorous plant, the Venus fly trap. The end of the fly trap's leaves looks like two oval lobes joined in the middle. On the surface of each oval lobe, there are three trigger hairs. When an insect lands on the lobe and touches the hairs, the lobes would fold closed around the insect, and its points would form a tiny cage that traps the insect alive. For the trap to be sprung, the trigger hairs must be touched multiple times. That way the plant knows whether what is in the trap is alive. Digestive enzymes are then released into the trap to finish the job. The pitcher plant is an excellent example of a passive trap. The plant has tall leaves, and water and digestive enzymes collected inside these leaves that form a reservoir at the bottom. Insects can be easily attracted to the plant and they would enter through the top of a leaf. As the insect proceeds down the inside of the leaf, small hairs inside the plant that point downward would direct the insect further and further into the center. What's more, the sides of the leaf are coated with a waxy, slippery substance. Eventually, the insect will fall into the water and drown. As the insect decomposes, it releases nutrients that feed the plant.