Question

3. --- ____ the sports meet might be put off． --- Yes，it all depends on the weather．

　　A． I've been told B． I've told 　C． I'm told D． I told，答案选A,但是想问下为什么不选C?

还有
4. I need one more stamp before my collection ___.
　　A. has completed B. completes 　C. has been completed D. is completed答案选D,为什么不选C?
5. Rainforests ___ and burned at such a speed that they will disappear from the earth in the near future.
　　A. cut B. are cut 　C. are being cut D. had been cut答案选C，而不选B？

谢谢大神

Answer 1

3.A 如果使用 I'm told 也应该是 I was told ,因为是发生过的事，用现在完成时还可以强调影响。
4.主句是一般现在时，从句一般也采用一般现在时。
5.C 表示正在进行，意义：雨林照这样的速度被砍伐下去很快就会从地球上消失。