Choose the best answer A, B, C or D to complete the following sentences

Air __________ is causing many environmental problems in our cities today.

The roof of the building __________ in a storm a few days ago.

The road in front of my office is always __________ when it rains heavily.

You are not allowed to use your mobile phone on the plane. (MUSTN’T)

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Singapore is famous for its __________ and green trees.

Rewrite the second sentence so that it has a similar meaning with the first one

Vietnamese students are obligated to wear uniforms when they go to school. (HAVE)

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In some English speaking countries, turkey is __________food at Christmas.

After I __________ in the room, she left.