cost是動詞，也是名詞。當名詞時，是花費、成本、代價等。當動詞時，是花費、使付出、使失去、估算成本等。
cost是及物動詞，也是不及物動詞。偶爾作系動詞,如That cost dear。具體使用如下:
1.花費
(1) sth cost (sb) 金錢 ( + to do sth)
It costs me too much to do that.
She doesn't want to cost 5,000 dollars to buy that machine.
The new car cost me 40,000 yuan.
The lost toy cost 9 dollars.
(2) doing sth cost (sb)時間
Playing with you cost me a lot of time.
Helping with housework cost me some days.
(不用具體時間，用籠統時間)
2.使失去、使付出
The accident cost me a friend.
The mistake will cost him the good job.
3.使做不愉快的事情
That thing cost my mother many sleepless nights.
Your suggestion cost me a visit to the hospital.
注意：以上三種情況，cost的過去式和過去分詞是cost，主語是物或事物，不能是人，無被動語態。
4. 計算費用、估算成本
The project was costed by the boss.
I have costed the new building.
注意：當計算費用、估算成本時，它的過去式和過去分詞是costed,主語是人，且有被動語態。