請教英文文法題

Question

以下是這三題英文文法題目：
1.The problem ....... overworking all day long impairs your health.
可以請教一下為什麼是填入is that而不是is，這裡是怎樣的句構呢？
(impairs 是子句的動詞嗎?????)
我拆解了好久喔！都想不出來，麻煩各位高手們幫我的忙，感激不盡啊！

2.We have been told the final outcome of the negotiation, but we shall never know
what.........on behind the scenes.

我的理解是這個what片語是當we的受詞，應該也用同樣的時態才對，但是這裡的空格給的答案，為什麼是填過去式的went呢？

3.I am afraid the express train will ...... by the time you get to the problem.

這裡的答案是have left，為什麼不用be left呢？


先感謝大家的回答，讓我的英文有進步長知識。

（目前正在努力學習英文的我）

不好意思打錯了，第二題我的理解應該是KNOW的受詞才對！@@

Answer 1

1. The problem is that overworking all day long imparies your health.
* The problem is that = it is that + tag sentense
that can not be skipped because the tag sentense is not an O. sentense.
* impair is the V. of tag sentense

2. The V. here shall be the same as the main sentense
*We have been told ......what went on behind...
According to the sentense, it is something happaned in the past.

3. When you want to show the timing of different events, using have +PP will show which event has happened.

View more questions and sample sentenses, you will get it.

Answer 2

1.The problem ＿ overworking all day long impairs your health.
填入is that之後，that overworking all day long impairs your health 就變成了名詞子句
用來補充敘述 The problem
這個問題是...是什麼?
就是超時工作會傷和健康

2.We have been told the final outcome of the negotiation, but we shall never know
what ＿ on behind the scenes.
填上went之後就是指
我們將不知道幕後還有什麼事繼續
what went on behind the scenes也是名詞子句
當作know的受詞

3.I am afraid the express train will ＿ by the time you get to the problem.
不能用be left是因為火車不能"被離開"
整句意思應該是
我怕你有事情時火車會離開
這個文法我還沒學過
不過我猜will have left
應該是強調火車會離開的這件事情