By the time I got outside, the school bus ________(leave)．
When I got home, my pet dog ________(lie)on the floor，dead.
Last Friday afternoon the young man ________(hurt) in the traffic accident which happened on the highway.
Every one of us was excited, for in a few minutes we ________(see) Liu Xiang appear on the sports ground.
The Women's World Cup ________(not begin) until 1991 when China hosted it in Guangzhou.
If those wild animals can't find enough food，they ________(die) or have to leave their habitat soon.
The law of gravity ________(discover)by Isaac Newton about 350 years ago.
Since last August，the old lady ________(have)bad headaches three to four times a month.
Bangkok，the capital of Thailand, ________(know)as the “City of Angels”．
Jack said he ________(return)the two books to the library in a week.