I wonder how much you charge for your services—- The first two are free ____ the third costs $30

What does the sign over there say?— No person _________ bring drinks into the student computer room.

You won the first prize in the last Physics competition once again.—__ _. I made several mistakes.

You’ll have to pay an extra amount tothe cost of insurance

依次填入下列各句横线处的成语，最恰当的一组是 （ ）①消防工作必须立足于_____，从提高公众的防火意识做起。②即使现有的产品杨销，也要_____，抓紧技术储备与新产品开发。③如果我们不从小事做起，_____，那些细小的苗头最终可能酿成大祸。