There are some warnings in some countries ______ over exploitation of underground water has caused the decline of wetland and increase of desertification.

______ what your families said just now, I think, and you will make your own decision.

______ watched the 2012 London Olympic Games agreed that some Chinese athletes performed perfectly, such as Sun Yang and Ye Shiwen.

It’s more than half a century ________ my grandfather joined the Party and became a servant to the people.

---What do you think of your parents?
---They always let me do ________ I think I should do.

_______ done for us?

      takes me several hours      my tasks. Because they are too difficult.

_____ you didn’t know the rules shouldn’t be an excuse for your failure to report. 

So______ that most parents are too worried to let their kids travel alone at the beginning of the new term.

At present, we are studying a total of nine subjects, ________ I think is physics.