Teachers be sensitive to the development level of each student so as to help them better.A

问题补充：

Teachers be sensitive to the development level of each student so as to help them better.

A. can

B. may

C. are able to

D. need to

答案：

A. can

B. may

C. are able to

(答案→)D. need to

解析：考察情态动词用法。A能够，可能；B也许；C能够；D需要；本题中的动词need是一个行为动词，后面直接接不定式；如果need作为情态动词，通常用于疑问句或者否定句。句义：为了帮助孩子们更好地发展，老师需要对每个孩子的发展水平很敏感。根据句义说明D正确。