用动词的适当形式填空
____________(study) Zhalong helps us learn about protecting wildlife.
Some of the students___________（remove）the snow when we arrived there.
One of my classmates __________________ ( be) to the Great Wall twice.
Father’s Day is coming, but I__________ (buy) a present for my father yet.
Tom ____________ (live) in Nanjing for ten months in 2005.
There__________ (be) many great changes in many areas in China since 2000.
The teacher has told us many times that light _____________ (travel) faster than sound.
We did everything we can____________ (protect) animals in danger.