Mr. Green _________ his son.—Yes, he enjoys talking about his son with any friend of his.

It was during World War II, ____ he was in his early twenties, _____ he joined the British Army

When was it youmet him in the library

Once environment damage _____, it takes many years for the system to recover

26．— Why are you still here? Everybody has gone to attend the lecture by the president— Oh, I__________about it!