动名词作为主语在英语中是很常见的，它们可以表示一个动作或状态，并且通常遵循主谓一致的原则，即谓语动词使用单数形式。以下是一些动名词做主语的例句：

Swimming is important for health.

Reading is an art.

Climbing mountains is really fun.

Working in these conditions is not a pleasure but a suffering.

It is no use crying over spilt milk.

There is no saying when he'll come.

No smoking.

Their coming to help was a great encouragement to us.

Smoking is prohibited here.

Collecting stamps is interesting.

Reading aloud is very helpful.

Fishing is a relaxing hobby.

Cycling is a great way to explore the countryside.

Dancing is a fun way to stay fit.

Jumping into the pool is refreshing.

Playing football is a popular sport.

Painting is a creative activity.

Writing is a great way to express oneself.

Speaking English is beneficial for travel.

Swimming is a good exercise for your whole body.

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。希望这些例句能帮助你更好地理解动名词作为主语的使用。