A想对 I employed someone to do something for me(我雇用了某人为我做事)这一类句子作更简洁的表达时，可以用这种结构：即不说 I employed someone to clean my car，而说 I had my car cleaned(我叫人擦了车子)。又如不说 I got a man to sweep my chimneys(这里got= paid/persuaded等)，而说I had my chimneys swept(我叫人通了烟囱)。
注意必须用have+宾语+过去分词，否则意思就变了：
He had his hair cut.
他理了发。相当于：
He employed someone to do it.
他雇人理发。
但是：
He had cut his hair.(过去完成时)
他自己理了发。(在说话之前的某个时刻他自己给自己理了发)
have这样用时，其否定式和疑问式的现在时和过去时都要用
do来构成：
-Do you have your windows cleaned evny month?
-I dont have them cleaned;I clean them myself.
-你每月都要叫人擦窗户吗?
-我不叫别人擦，我自己擦。
He was talking about having central heating put in.Did he have it put in in the end?
他那会儿总说要找人装暖气。到底装上了没有?
这种结构可以用于进行时态：
I cant ask you to dinner this week as I am having my house painted at the moment.
这一周我不能请你来吃饭了，因为现在我正让人刷房子呢。
While I was having my hair done the police towed away my car.
我(让人)做头发时，警察把我的汽车拖走了。
The house is too small and he is having a room built on.
房子太小了，他正叫人添盖一个房间。
get能够像have一样用于上述句中，但更口语化。句中提到完成动作的那个人的时候，也可以用get：
She got him to dig away the snow.
她让他把雪挖走。(她雇/说服他)
(have与不带to的不定式连用也能起同样的作用，如She hadhim dig away the snow。但在英国英语中get结构要常用得多。)
B have+宾语+过去分词结构在口语中可以用来代替常表示意外或不幸遭遇的被动态动词。如 His fruit was stolen before hehad a chance to pick it(他树上的果子还没来得及摘就被人偷掉了)可由He had his fruit stolen before he had a chance topick it来代替。Two of his teeth were knoceked out in the fight(他的两颗牙在打架中被打掉了)可由He had two of his teethknocked out来代替。
在本节A中，可以看到主语是命令别人做某事的人，而在这儿，主语则是承受行为结果的人。这里主语也可以是物：
The houses had their roofs ripped off by the gale.
房子被狂风掀掉了屋顶。
这里也可以用get代替have：
The cat got her tail singed through sitting too near the fire.
猫坐得太靠近炉火，尾巴上的毛被烤焦了。