To learn a foreign language is an ________ thing.

[　　]

Mr Wang ________ cold for two days.

[　　]

You must keep your classroom ________ .

[　　]

You can see a ________ man in the photo.

[　　]

A．21 years old

B．21-years-old

C．21 year old

D．21-year-old

I ________ (that)I shall be back until eight o'clock.

[　　]

A．didn't suppose

B．don't suppose

C．never supposed

D．supposed

The colorful bright lanterns ________ the night.

[　　]

At night people gazed ________ the full，round moon.

[　　]

Linda couldn't see Alice ________.

[　　]

The boy is running ________ a big dog.

[　　]

The old man was ill. Now he is ________.

[　　]

A．in the hospital

B．in hospital

C．at hospital

D．at the hospital