1、可以省略to be的系动词,比如:seem, appear, turn out The examination turned out( to be)easy.结果是考试很容易。
The baby appears(to be) hungry 宝宝似乎是饿了。
She doesn't want to go on studying. It seems a pity 她不想学下去了,这似乎很可惜。
2、作系动词的感官动词,比如:look,feel, sound, taste, smell Tom felt sleepy so he decided to take a nap 汤姆感到困了,所以决定小睡一会儿。
You sound unhappy. what's the matter? 你说话听起来不高兴。怎么回事?
3、表示变化的系动词,比如:go,get,fall,turn,grow, become等。如:
fall ill生病, fall asleep睡熟, turn writer= become a writer成为作家, go bad/mad/ blind/ grey/pale变坏/变疯/变瞎/头发变白/脸变苍白, go unnoticed未被注意到, get hurt受伤, get angry生气