系动词
（一）系动词包括be动词和半系动词.
（二）半系动词的用法：
1. 常见的半系动词有：get (变得), turn (变得), grow (变得), become (变得), fall (变得), look (看起来), sound (听起来), feel (摸起来), smell (闻起来), taste (尝起来), keep (保持), stay (保持), remain (保持), seem (似乎)等.
2. 半系动词的特点：
(1)半系动词在疑问、否定、倒装时,跟实义动词一样,都是借助于助动词.如 Do they look young? (疑问) / I didn’t feel very well yesterday. (否定) / That sounds interesting, doesn’t it? (倒装)
(2)半系动词后面可接形容词,这一点是实义动词所不具备的,它更象be动词,所以被称作半系动词.如 The cake tastes delicious.
(3)半系动词通常不用被动语态.如 The house looks big.