I need 50 yuan to ___ for winter camp. I have to ask my father for some money.

Whataretheydoing?They’retraining______acharitywalk. [ ]

What do you think of the film called Inception《盗梦空间》?—The film is full of suspense (悬念). I should say the screen-writer is really ______.

He spoke English so well that I took _______ for granted that he was an American.

How long have you been writing letters in English?— .[ ]