从各题的A、B、C三个选项中，找出和画线部分意思相同或相近、并能替换画线部分的选项。

1．If you are free at the moment，please clean your bedroom yourself．

A．at once               B．right now          C．right away

2．Could you give me one more chance? I'll try my best to succeed．

A．two                B．the other          C．another

3．Doing exercise every day can make you stay healthy．

A．live                 B．keep               C．become

4．I am really anxious，for I can't find my backpack．

A．worried                  B．angry              C．disappointed

5．We are not certain if it will be fine tomorrow．

A．exact            B．convincing          C．sure