高一 英语 英语 请详细解答,谢谢! (5 17:36:42)

----she couldn’t understand was-----few and few students show
interest in her class。第二个空是填that.
你想想she couldn’t understand why few and few students show
interest in her class。是不是更通顺一些？其实few and few students show
interest in her class。作表语
pay back：偿还
pay off ：还清，强调一次性还清

1.(What)she couldn’t understand was (why) few and few students show
interest in her class.为正确表达。其中(What) she couldn’t understand 为主语从句，(why) few and few students show
interest in her class是表语从句。
另外，省去前面的疑问代词what，变为“She couldn't understand why few and few students show interest in her class。”也是对的。此时，“why few and few students show interest in her class。”则成了宾语从句。

pay back和pay off是两个不同的词组。
pay back“偿还”，借了别人的钱，还给人家叫pay back。
pay off“还请债务”

应该用that,why不能用作...
pay back
偿还，还钱给(某人)；回报，向…报复
vt. 偿付(还击)

pay off
还清；付清；行贿；取得成功
偿清(欠款等),贿赂

这题怎么看着有问题啊？是不是不完整啊？怎么可能在一个句子里出现两个动词呢？She的前面是不是还有个词啊？
把she couldn't understand 这个句子当成主语的话 填 that，引导一个表语从句。让她不能理解的是学生们对她课的兴趣越来越少了。
pay back 偿还
pay off 还清

What...why...

Pay back: 偿还。多为先欠（钱，物，情）后还时用。
Pay off: 多为付出（努力，心血等）之后，表应得的回报，如Your efforts will get pay off. 不一定有欠...在先。

我觉得句子有问题，怎么会有2个动词？
我想（What ）she couldn't understand was （that ）few and few students show interest in her class。是完整的句子吧

前面是一个表示疑问的陈述，那个that后面就是为了解释那个What

pay back 偿还
pay off 还清