People should ______ from ______ down the trees to protect the earth.

I hear the hospital is more than 30 years old.— Yeah, the government ______ it in 1980.

_____ successful launching of Tiangong-1,China’s space dream has taken ______ step closer to reality

I must __________ my school ID card. Can you help me

Dad, science is too hard for me.—Oh, dear, if you keep listening ________ in class and do enough exercises, you’ll find it easy.