Scientists in some countries have done a lot of work to _____ the moon.

I didn’t ________ my primary school classmate Jane until I listened to her self-­introduction. 

Two percent of the total poulation of China have ____ access to the Internet,____ with 45 percent in the USA and 15 percent in Japan.

I support your decision, but I should also make it clear that I am not going to be __________ to carry it out.

He telephoned the travel agency to_______three air tickets to London.