小题1: Which road sign tells us that we must NOT turn right?

小题2:Outside our school there’s a sign like this. What should the drivers to when they see it?

A．They must stop the car immediately and wait there.

B．They must take a U-turn there.

C．They mustn’t even stop the car in that area.

D．They mustn’t drive the car into that area.

碳水化合物是构成机体和参与细胞代谢活动的重要物质。