怎么样用“ask sb to do sth”造句？

比如说，“我请求小明去帮我买本书”，可以这样造句，"I ask Xiao Ming to help me buy a book."  

再举一个例子: “老师要求学生按时完成作业”，可以这样造句，"Teacher ask student to finish the homework on time."

Teacher ask student to finish the homework on time."

ask sb to do sth
要求某人做某事。
ask

v.询问；请求；邀请；要求；开价；期待
例句
用作动词 (v.)
May I ask a question?
我可以问一个问题吗？
He'll lend you the money if you ask him.
如果你请求他的话，他就会把钱借给你。
It was such a big job that he had to ask for help .
这项工作量太大，他得请求帮助。
I have asked some friends for tea.
我请了一些朋友来喝茶。
I have the right to ask for an explanation.
我有权要求一个解释。
My father ask me to account for my conduct.
我父亲要求我为自己的行为负责。
The man asked ten dollars for the book.
那个人竟然给这本书开价十美元。
As parents, we should not ask too much of our children.
作为父母,我们不应该过分要求孩子。

1. Tell ( ask ) sb  to do sth.                  

要求 ( 吩咐 ) 某人做某事.

2.  It is important for sb . to do sth.                                    

某人做某事是很重要的.

3.  It is wrong of sb . to do sth.                                     

某人做某事是错误的.

4.  It is essential for sb . to do sth.                                     

对某人来说做某事是绝对必要的.

5.  It is possible for sb to do sth.                                     

对于某人来说做某事是可能的.

6. It is time for sb . to do sth.                                     

该是某人做某事的时候了.

7. I've come to ask you to do me a favour.                                    

我来这儿是想请你帮个忙。

8.  Ask Neil to do it — he's a dab hand at carpentry.                                     

让尼尔来做吧,他做木工活很在行.

来自《简明英汉词典》

9.  It would be unthinkable to ask him to do that.                                     

叫他做那件事是毫无可能的.

来自《简明英汉词典》

10. When people ask you to do something, you should take It'seriously.                         

人家托你的事, 你别不在意.

来自《现代汉英综合大词典》