though,although,as,but,however,since这些词怎么用答:however连接词 conj.1. 然而,可是,不过 I feel a bit tired. However, I can hold on.我有点累了,但我能坚持下去.副词 ad.1. 无论如何,不管怎样 However hot it is, he will not take off his coat.无论多热,他也不会脱掉外衣. 2. 不管用什么方法 However he tries, he never seems...
is,am,are,was,were,being,been,to be怎么用答:is am are 用在一般现在时的句子中 were was 用在一般过去式的句子中 being 可以和别的助动词构成别的时态,例如will be beding.../have been being...been to 用在have/has been to中 意为曾经到过.to be一般用在非谓语中,例如, there are so many things to be done.