1·A cloth covers your couch; keep it clean!
覆盖在沙发上的布要保持干净！
2·To keep it clean, we can sweep the floor.
为了保持它的干净，我们可以扫地。
3·It is our duty to keep it clean and tidy.
这是我们的责任保持干净整洁。
4·The earth is our home. We must keep it clean.
地球是我们的家，我们必须使他保持干净。
6·Hey, hey, keep it clean. There are ladies present.
嗨，别说难听话了，有女士在场呢。
7·You may use the room so long as you keep it clean.
你可以使用这个房间，只要你能保持干净。
8·You may borrow my book as long as you keep it clean.
只要你保持书的清洁，你就可以把我的书借去。
9·While you keep it clean, I can lend the book to you.
只要不把书弄脏，我可以借给你。
10·You may borrow the book so long AS you keep it clean.
只要你保持这书清洁，你就可以借它。