________ ! Somebody has left the lab door open.—Don’t look at me.

单项选择（每题1分）We must think twice _____ we make the final decision

We are told that more new teaching buildings ________ next year.

Believe it or not, my sister and I are twins. — Oh, you must have had the case _____you were taken for your sister. [ ]

do you think of your new colleagues—They are mostly very kind,but________is sogood to me as John