可不可以用be doing,when be doing?

可不可以用be doing,when be doing? be doing sth.when when 后面可不可以接doing sth 用be+doing +when be用be+doing +when be +about to do+when.be+On the point of doing +when.has just done +when +did..各造两个句子! 用be doing when do造5句 用when be doing/do/does句型造十个句子 用be doing when do造5句,是陈述句, 用be doing when do造5句,是陈述句, 帮忙用was/were doing .when ; be about to do.when;had just done.when造句, when he _____something useful,he wasted his time drawing little pictures.a.must have done b.shall be doing c.should be doing d.should have been doing 如何对be doing sth when造句 Tom pretened ---his homework when the teacher came in.A.to be doing B.to do Student are told _____ very careful when they are doing experiments. A should be B.be C. to be D.will be为什么选C,理由一定要详细.tell sb sth 为什么这里用to be 可不可以be good at clean 或者doing clean be stopped from doing中的from可不可以删去? 用be+doing 造句^-^ 各举一个be+doing+while+be+doing和be+doing+when+did的例句,be最好为过去时 we will be farther along than when we started中的farther 可不可以用further