Be careful with that knife,or you'll cut ________.

Are there differences between you ________ them?

You may use it ________ a house.

There is no difference between the two words. I really don't know ________.

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Now many children like surfing on the Internet, but ________ the same time they should know that there is something unhealthy on it.

Where is your mother? I can't find ________ anywhere.

Would you please tell me ________ next, Mr Wang?

The Changjiang River is the ________ river in Chine.

He has worked ________ a teacher for ten years.

My mother often ________ cakes for me.