Not believing their eyes, the visitors on the spot_______ the flying plane, doing some most difficult and dangerous tricks in the sky. [ ]

It’s dangerous to swim here. Look at the sign.–Oh, I it. Thank you.

zy boy is indeed unusual: he knows nothing,______ does he seek to know

Giving children pocket money as a giftduring the Spring Festival is a common _______ in China

Seems you are quite familiar with Russia.—That is because I _________ the country in 1999