She laughed happily 和 She looked happy 两句都对，那到底什么时候用happy？什么时候用happily ?
如果要强调动词进行的的状态或程度，要用副词来表示－
(动词+副词) 就像同事Kevin说了一个笑话，Amy觉得有趣，笑得好开心，不只有微笑而已，而是开怀快乐地笑，在程度上是有差别的，所以我们说 :
(O) She laughed happily. (她笑得很开心)
(X) She laughed happy.
同样的道理，以下这句话是Tom不只有开车而已，而是很谨慎地开。如果只有开车， Tom drives. 就可以了。但如果开车的状态有区别，那说法就不同了，所以要说 :
(O) Tom drives carefully. (Tom开车很小心)
(X) Tom drives careful.
接下来这句话，同样的道理，不是只有说话而已，而是强调小声地说，所以是 :
(O) Please speak quietly. (请说话小声点)
(X) Please speak quiet.
但是另一方面，英文有一组连缀动词 ( linking verbs ) ，表达的不是动词进行程度上的差异，而纯粹只是连结、描述或补充说明主词的意义或形式，后面接形容词－
(连缀动词+形容词) 常见的连缀动词有:
be 动词 –
Jeff is intelligent. Jeff很聪明
look (看起来) –
That chair looks comfortable. 那把椅子看起来好舒服
seem (似乎) –
Eddy seems drunk. Eddy似乎喝醉了
appear (看起来好像是) –
Rose appeared calm in the interview.
Rose在面试中好像很镇定
feel (感觉) –
I feel safe when Jack is driving.
Jack开车时我觉得很安全
sound (听起来) –
Meg’s suggestion sounds interesting.
Meg的建议很有趣
smell (闻起来) –
The soup smells good.
这汤闻起来真好
taste (尝起来) –
The sauce tastes strange.
这酱汁尝起来很奇怪
remain (保持) –
Jenny remained silent.
Jenny保持沉默
become (变成) –
The problem became worse.
这问题变得越糟了
grow (变成) –
Linda was growing bored.
Linda开始觉得无聊了
turn (变成) –
The weather has suddenly turned cold.
天气突然变冷了
go (变得) –
If anything goes wrong, call me right away.
如果出了什么错，立刻打电话给我
get (变得) –
If you get upset with me for this, I won’t blame you.
如果你因为这件事对我不高兴，我不怪你
prove (证明) –
The medicine proves effective. 这药证实是有效的
