下列药物知识中正确的是( )
开学初，小芳和小亮去文具店购买商品，小芳用18元买了1支钢笔和3本笔记本，小亮用31元买了同样的钢笔2支和笔记本5本，求每支钢笔和笔记本的单价．
— What time do you get home?
— At_______.
Only good swimmers can get to that place. There is water all ________ it.
