英语语法分析

This doesn't usually have a groundsheet but you can buy one to fit, though it costs extra.

这通常没有防潮布，虽然会产生额外的费用，但是你可以买一个跟它配套。

There is usually an outer tent of water-proofed fabric and a lighter inner tent or tent with a built-in groundsheet.

通常有一个防水布料构成的外部帐篷和一个较轻的或带有内置防潮布的内部帐篷。

There is usually an outer tent of water-proofed fabric and a lighter inner tent or tents with a built-in groundsheet.

通常有一个防水织物的外部帐篷和一个或多个带有内置防潮布的较轻的内部帐篷。