知识点1:从句作主语一定要按单数主语看待。
［误］ What he said are right
［正］ What he said is right
［析］ 从句作主语一定要按单数主语看待。
［正］ The rich is not always happy

知识点2:从句主语时谓语用单数还是复数
Whoever breaks this law deserves a fine. 违反本法者应予以罚款。
若用作主语的是what引导的从句，且其后为系表结构，此时需注意以下两点：
1. 若表语为复数，主句谓语通常用复数。如：
What I want are details. 我要的是细节。
What is needed are rational and firm actions. 所需要的是合理的坚决的行动。
2. 若what从句中的what表复数意义，则主句谓语动词要用复数。如：[1]谓语动词,动词,相关知识点

谓语动词切忌用“行为动词1 + 原形动词”、“be + 原形动词”。○4have+过去分词。如：Many trees have been cut down since 1970s.（意思同上）○5般时问句和否定句中：do/does/did+原形动词。如：He does not enjoy himself very much.（他日子过的不好。）Did any of you se

His muscles were wasting away, and what were left were flabby. 他的肌肉正在消耗，所剩下的就是松弛的皮肉。