—_____ swim in the river?

— oh, no. Our teacher told us ____ here. It’s dangerous.

A．Why don’t; not swim

B．Why not; not to swim

C．Why not; don’t swim

D．Why don’t; don’t swim

DNA双链中，指导合成RNA的那条链称作

A．编码链

B．有意义链

C．非编码链

D．模板链