把下列句子变为被动语态：

The doctor is operating on the boy.

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把下列句子变为被动语态：

Our English teacher often tells us to speak English in class.

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把下列句子变为被动语态：

The boss didn't make you carry these heavy boxes.

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把下列句子变为被动语态：

People know that he is able to do it well.

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把下列句子变为被动语态：

The students must hand in their English exercise books before they leave school.

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把下列句子变为被动语态：

The workers have finished building the bridge.

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改主动语态为被动语态：

People are still cutting down too many trees in the USA.

把下面两句变为被动语态：

1．We always keep the classroom clean.

2．His mother has made him do the housework.

把下面句子变为被动语态：

People must take good care of older people.

把下面的句子变为被动语态：

Everyone likes Spring Festival in China.