We must start to do the work right now____we don't have enough timea.because b.whenc.ifd.though今天急用.

we must start tomorrow morning. We must start to do the work right now____we don't have enough timea.because b.whenc.ifd.though今天急用. We must do ( )the people want us to do. We must start early,（ ） it will take two hours to drive to the airport. do you start to Must we 【start】 the work at once __(不管怎样),we must start now. we must start early,____we have a long way to go.Abecause Bfor start to do 和 start doing 区别 start dong 还是start to do sth start to do 和start doing We must do our ____ to help them 填什么 We must do everything possible to keep them ____(safety) We must do something to help her被动语态 We must spare no effort to do it. We must do more exercise often to p__ the disease We must do something to change their _(生活). We don`t know when we shall start .(改为to do 的结构） We don`t know when ____ _____.说出语法！to start