托福TPO56听力原文+题目+答案解析：listening L4

发布时间：2020-12-18 15:02

1托福TPO56听力原文：L4

Listen to part of a lecture in an environmental science class.

Before we get started, I want to tell you a little story. I guess it was about ten years ago, I decided...with my family, I decided it was time to buy a house. And my two kids really wanted a house near the ocean as close to the beach as possible. Well, I try to explain all the reasons that building near the ocean just didn't make sense environmentally, but the kids still wanted a house near the ocean. So my wife and I looked at a few houses and they were beautiful. There was one we saw that I still call our family's dream house. But we were lucky. Um, and I'll tell you why in a moment.Um, when we realized that we just couldn't afford any of those houses.

So I said building near the ocean doesn't make sense environmentally. But what is it about the coastal environment that makes most of the land there unsuitable as a building site? Let me explain coastal zones first. Imagine standing at the water's edge and moving away from the ocean. We come across different coastal zones, going in order, they are the beach, which I'm sure you're all familiar with.Second is the _______ dune, which is the most _______ zone. Next is the trough. That's trough,trough, after the trough is the secondary dune. And finally you come to what's called the back dune.

So the beach, if I say it's not advisable to build houses on the beach, uh, right on the _______, I don't think you'd find it difficult to imagine why. You've got the sand, which is not very supportive for building, and you've got daily _______ fluctuations. Keep in mind too, that the sands are always shifting and the shore line is moving. Right near here, you've got sandy _______, and you can walk out on that peninsula almost a mile to sandy point. But it wasn't that long ago, I think, back when my grandfather was a boy, that sandy point was an island, and you couldn't just walk there from the mainland. Right? The sands shift and the shore land moved. Before we continue this imaginary walk. I want you to think for a minute. Why are these coastal zones important? Well, environmentally, their role is protecting the inshore area, from being flooded with salt water, from being damaged during storms, and they allow vegetation to grow further inland by providing sort of a _______ zone to protect against wind and salt spray.

All right, let's go back to our walk on the beach. Okay, after the beach, I said, you've got the primary dune. Now you shouldn't build on a beach, but it's ok for _______, that's good. But the primary doom really cannot support building or recreation. It's more sensitive than the beach. If you think of a sand dune as just a windblown pile of sand, that's wrong. Sand dunes can support vegetation. And the primary dune is where the vegetation first begins to take hold, but it's fragile and easily disturbed. And what happens when the vegetation is disturbed is that the sand dunes from the beach can _______ inland, leaving less sand on the beach and less sand on the beach. Well, that's beach erosion.You've probably seen beaches which used to be very wide that seem to be _______. Beach erosion is often caused by destroying the primary dune.

After the primary doom, we come to the trough. Now the trough is _______ of limited recreational use and some building. The vegetation is thicker and the ground more stable. Care should be taken to preserve the quality of the ground water. But in general, it’s okay to build here. After the trough is the secondary dune. This is sort of the final defense against the sea. And like the primary doom, no building should take place here. The last zone will look at is the back down. It's further inland and more suitable for development than any of the other zones.

So the first two zones we looked at, the beach and the primary doom are probably the worst places for building. And where do people most want to build? Exactly, the beach and the primary dune. We're talking about very valuable real _______ right on the ocean. I mean to build on the beach. Today, you may be a hundred meters from the water's edge, and in a few years, the water's edge may be right in your living room. And that's what happened to our dream house. A storm brought the water's edge right up to the house. Afterwards, the water receded, but the action of the waves removed so much sand that the house was now unstable. It was now impossible to live in this beautiful and very expensive house.