动名词可以在句子中充当主语，表示一个动作或状态。以下是一些动名词做主语的例句：

Swimming is a good exercise for your whole body.

Reading is an art.

Climbing mountains is really fun.

Doing much exercise is good for our health.

Listening to the music is good.

Throwing litter about is very bad.

It is no use crying over spilt milk.

It is a waste of time persuading such a person to join us.

There is no saying when he'll come.

No smoking.

No parking.

Their coming to help was a great encouragement to us.

Reading aloud is very helpful.

Collecting stamps is interesting.

It's no use quarrelling.

Practising any skill for 10,000 hours is enough to make you an expert.

这些例句展示了动名词在句子中作为主语的各种用法，包括直接位于句首、用it作形式主语、用于“There be”结构中、用于布告形式的省略结构中以及动名词的复合结构作主语等。