19  An endangered species of whale is experiencing a small baby boom of the coast of America. The North Atlantic right whale is one of the rarest species of whale on the planet, numbering only about 411. But the Center for Coastal Studies said Friday that its aerial survey team spotted a mom with two babies in Cape Cod Bay a day earlier. That brings the number seen in nearby waters alone this year to 3. That's big news because the whale population has been falling and no baby whales were seen last year. In all, seven baby whales have been spotted so far this year.  20  The whale population has become endangered due to commercial whaling activities in recent years. This is because they are sometimes hunted for their meat or their skin. Over-hunting could lead to the disappearance of the whale population, possibly causing major problems to the global food chain.  21  The whales give birth off the southeast coast of America in the winter and travel to feeding grounds of the northeast coast in the early spring. Northeast coast is a critically important source of food. The animals often feed close to shore. This provides watchers on land with unbeatable views of one of the rarest of marine mammals. It's illegal to get within 1,500 feet of the animals without a federal research permit, so whale watchers are discouraged from attempting to get close to the whales.

 19  一种濒临灭绝的鲸鱼正在美国海岸经历着小婴儿潮。北大西洋露脊鲸是地球上最稀有的鲸鱼物种之一，大约只有411头。但是海岸研究中心星期五称，一天前，其航测队在鳕鱼岬海湾发现了一头有两个幼鲸的母鲸。这使得今年仅在附近海域发现的鲸鱼数量增至3头。这是个大新闻，因为鲸鱼数量一直在下降，去年没有看到幼鲸。到目前为止，今年总共发现了7头幼鲸。 20  近年来，由于商业捕鲸活动，鲸鱼种群已濒临灭绝。这是因为它们有时因其肉或皮而遭捕杀。过度捕杀可能导致鲸鱼种群的消失，可能会给全球食物链带来重大问题。 21  冬季，这些鲸鱼在美国东南海岸附近分娩，并在早春前往美国东北海岸的觅食地。东北海岸是极其重要的食物来源。这些动物经常在近岸觅食。这使得陆上观察者可以一览最稀有的海洋哺乳动物之一那无与伦比的景象。在没有联邦研究许可的情况下，在1500英尺范围以内接近这些动物是违法的，因此，鲸鱼观察者被劝阻不要试图接近鲸鱼。

19.从这篇文章中，我们了解到了关于北大西洋露脊鲸的哪些信息？

A)它一次产下几个幼崽。

B)它是最不受保护的哺乳动物物种。

C)它的繁殖地现在得到了更好的保护。

D)它的数量现在有增加的迹象。

20.是什么导致了近年来鲸鱼数量的下降？

A)全球变暖。

B)污染的海水。

C)商业捕鲸。

D)出生率下降。

21.鲸鱼在早春游至美国东北海岸的目的是什么？

A)交配。

B)寻找食物。

C)躲避猎人。

D)寻找繁殖地。