The streets are crowded (at/ in/ with/ of) vehicles at the rush hour.

Vietnam carried _________an intensive program for its athletics, which included training in facilities, both home and abroad.

The air at the seaside is good (at/for/on/of) health.

We are proud (at /in/on/of) our people's heroic tradition.

What did Mr. Brown die ..........?

There is an increasing demand _____ taller building in big cities.

I'm not acquainted (at/in/with/of) those flowers.

Look! That car is .............. ! Someone calls the fire brigade.

Thank you. It was very kind _________ you to help me.

No one knew precisely what would happen _____________ a human being in space.

He stayed home .......... the rain.

Who is not for me is .......... me.

John has gone away. He’ll be back ......... a week.

She likes to go .......... a picnic.

Jane doesn't spend much money______ clothes.

It was very kind .......... you to lend me the money I needed.

We started our journey ______ foot.

I keep sneezing because I got wet_________ the way home yesterday.

I was disappointed ________ the grade I received on my last essay. 

Her parents are very pleased _______________ her French.

Clean air is necessary ........... our health.