The washing machines sold in this shop are ________ to repair.

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A．free in charge

B．free on charge

C．free of charge

D．free to charge

How much will you ________ the new car?

[　　]

The electricity bill is ________ every month.

[　　]

A．due to be paid

B．due to pay

C．due paying

D．due being paid

________ the beginning it was difficult to hear people ________ long distances.

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________do you come to school? By bike.

[　　]

A．When

B．How

________are you staying in Xi'an？  Two weeks.

[　　]

A．How long

B．How far

________ you have done might do harm to other people.

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The farmer can sell their beef ________ in the capital.

[　　]

A．in the low price

B．at a high price

We can see the wild birds ________ along the river every day.

[　　]

A．fly

B．flying

The reason why he was late was ________ he had missed the bus.

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