Before breakfast, they often climbed a ________ hill.

[　　]

Not until I began to work ________ how much time I had wasted.

(重庆市2006)

My grandma didn't go to sleep ________ I go back home.

[　　]

I know him by ________ chance.

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(长沙市2006)

--- When did your father come back last night?

--- He didn't come back ________ he finished all the work.

[　　]

(北京市2005)

--- It's 9 o'clock now. I must go.

--- It's raining outside. Don't leave ________ it stops.

[　　]

At first he was strongly against our idea, but ________ the end he gave in.

[　　]

I took your book ________ mistake.

[　　]

(河北省2004)

Oh, the milk ________ strange, do you think it's OK to drink?

[　　]

(呼和浩特市2004)

An expert once said that humans ________ have serious problems in the future.

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