is后面加不定式,表示should?must?还是什么?作文中这种用法怎么样?therefore,thefirstway,thelastwayandthenever-failingwaytoovercomethisdifficultyistopracticeall-roundeducation.

Question

is后面加不定式,表示should?must?还是什么?作文中 这种用法怎么样?
therefore,the first way,the last way and the never-failing way to overcome this difficulty is to practice all-round education.

Answer 1

be to 意思是：（方法）就是；用来；想要和should或must无关例如：A knife is to cut with.【用来】A good way to keep healthy is to excercise.【（方法）就是】About eight hours must be spent in sleep if one ...