曼哈顿语法书里一问

Bestrong16

曼哈顿书里说（Chapter 13):
Sometimes the GMAT uses modal verbs (or their substitutes, such as have to for must) in a redundant or awkward manner. The idea of obligation or advisability may already be expressed elsewhere, or the modal verb may be place in the wrong part of the sentence.

Wrong:  This plan ensures that action MUST be taken.
Right:    This plan ensures that action WILL be taken.

为啥第一句不对啊。。之前的分析和这两个例句有啥联系？

scylarmartin

ensure已经有“确保”的意思了，再用must有些重复

UTADA_HIKARU

楼上+1
ensure和must语义重复

Bestrong16

Thanks!