请问We should learn to be grateful,为什么要加to be?

We should learn to grow we should learn to prop up ourselves 请问We should learn to be grateful,为什么要加to be? we should learn to be i__ when we grow up. We should learn to look after _____ first.(we) wo should try to learn best改成同义句We should _______ ______ _______ to learn we should learn 英语翻译We should learn to ___ ___ ___. we should try our best to learn them well. we should learn to live with our weakness.翻译 we should try our b_ to learn English weel. 英语作文we should learn (to)…… We should learn how to p( ) ourselves at any time. we should try to learn best（改为同义句） we_____ _____ _____ to learn we should try to learn best（改为同意句） we_____ _____ _____ to learn we should learn from lei We should learn( )Lei Feng. To learn English well ,We should find opportunities to English ----a much as we can