请选择并作详细解释
1 I think it is right to help those people in trouble.
I think it ( )( )( ) those people in trouble.
2 The newspaper came an hour ago, but I ()(not read)it yet.
为什么填haven’t read不填hadn’t read
3 The glass is broken. I ( )(break )by my brother.
为什么填was broken不填is broken
4Look, The train()just()(arrive)
为什么填has,arrived不填is ,arriving
5 She( )the dictionary to Alice yet.
A has returned B hasn’t returned

1.I think it right to help those people in trouble.
2 因为这张报纸是从一小时前来直到现在我还没读呢。表示某一动作从过去某一时间一直延续到现在用现在完成时。如果是明确到过去某一时间为止，才用过去完成时。
3 因为玻璃被打碎的动作发生在过去，即说话前发生的，所以用过去时。如果没有后面的by...，可以说it is broken.它（现在是）碎了（的）。
4。arrive，come等表示位置移动的词多用进行时表示将来。
5 。yet用于否定句末尾。所以这题用hasn't returned.