i borrow books once a week.books和once之间要不要弄什么

once a week和twice a week I eat junk food once a week.对once提问 i go to ---- cinema once a week I go swimming once a week 英译汉 I go swimming once a week.意思 once a week 意思once a week I borrow books about them. 对once a week提问用什么 once a week用什么时态 句子中once a week前要不要加介词at? I visit my grandparents once a week对once a week提问,怎样写