英语动词后面加S主要有两种情况:一是当主语是第三人称单数时,动词要加S,特别是以s, x, ch, sh或o结尾的动词要加es;二是现在分词形式,以-ing结尾的动词有时也需要加S。但是,情态动词、助动词、不规则动词等不需要加S。
1. 第三人称单数
当主语是第三人称单数时,动词要加S。例如:
- He plays basketball every day. (他每天都打篮球。)
- She runs in the park every morning. (她每天早上在公园跑步。)
- The cat sleeps on the sofa. (这只猫在沙发上睡觉。)
注意,当主语是第三人称单数,而且动词以s, x, ch, sh或o结尾时,要在动词后面加es。例如:
- He watches TV every night. (他每晚看电视。)
- She fixes her car by herself. (她自己修车。)
- The dog barks at strangers. (这只狗对陌生人叫。)
- The box goes under the bed. (盒子放在床底下。)
2. 现在分词
现在分词是以-ing结尾的动词形式,有时候也需要在动词后面加S。例如:
- The children are playing in the park. (孩子们在公园里玩。)
- I am learning English every day. (我每天学英语。)
- She is dancing with her friends. (她和她的朋友们跳舞。)