为什么下句不是You would better be more careful with you work,的缩写?

为什么下句不是You would better be more careful with you work,的缩写? You'd better be more careful with your work.(改为否定句） you need to be more careful.(保持原句意思) you'd better是you would better还是you had better的缩写?两者什么区别? life would be better with you by my side You would better be more ___(cheer) .tomorrow you will be be When____the work,you must be careful. 不是副词修饰动词吗?为什么是you have to be careful? careful不是形容词吗? you must be careful.为什么说careful没有be不能形成谓语,不是有must吗 Do you work with more _____?A.carefully B.careful C.careless you had better be careful.had better 的词性是情态动词,be careful词性是名 You should be more careful next time.