With the help of the high technology, this year the factory has produced ________ it did last year.

Not until all the fish died in the river      how specious the pollution was. 

_______ , and he felt hopeless.

It was the first time that I __________ the night face to face.

---You look unhappy, what’s happening, my son? ---I’m wondering how long it’ll be________ we come to China again.