Find out a mistake in the following sentence and correct it （找出句中的错误，并改正）：

TellA  pupils don’tB write onC the walls ofD the classroom.

Find out a mistake in the following sentence and correct it （找出句中的错误，并改正）：

I layA the picture onB your desk twentyC minutes agoD.

Find out a mistake in the following sentence and correct it （找出句中的错误，并改正）：

I hopeAyou to beB givenC a medalD.

Find out a mistake in the following sentence and correct it （找出句中的错误，并改正）：

DoA you see whatB easy itC is to useD the dictionary?

Find out a mistake in the following sentence and correct it （找出句中的错误，并改正）：

I adviseA you to stopB to thinkC of carrying out such aD dangerous plan.

Find out a mistake in the following sentence and correct it（找出句中错误，并改正）：

He ran soA quickB as toC catch up withD his friends.

Find out a mistake in the following sentence and correct it（找出句中错误，并改正）：

Look( A ), Tom is running the risk to save( B ) the drowning( C ) boy. Let's( D ) help him.

Find out a mistake in the following sentence and correct it（找出句中错误，并改正）：

Buttons mayA be mistaken for sweetsB and shouldC be kept whichDchildren cannot find them.

Find out a mistake in the following sentence and correct it（找出句中错误，并改正）：

One( A ) of the commonest cause( B ) of traffic accidents( C ) is that( D ) people don't  obey traffic rules.

Find out a mistake in the following sentence and correct if (找出句中的错误，并改正)：

He is the only one of the students who are often praised by the teacher

[　　]

A．is 　　 B．the students

C．are 　　D．by