The little fat professor is very popular with his students because he is good at ________ different teaching methods to make his class lively and interesting. [ ]

She told us what she bought yesterday ________ a fewapples and some clothing

I would never trust him again. He let me down.—— ________.

China made its firm ____ to cut carbon emissions in 2009.

下面各句中，表达得体的一句是