In case of emergency, whether knowing how to apply first aid or not really ________ in matters concerning wounds like swollen wrists, broken arms, burns, cuts, and so on.

 In case of fire, stay low to the ground in a smoky room, ________ smoke always rises towards the ceiling.

A. as           B. when            C. while             D. once

In case of emergency, whether knowing how to apply first aid or not really ________ in matters concerning wounds like swollen wrists, broken arms, burns, cuts, and so on.

A．makes difference                       B．makes a difference

C．makes differences                       D．makes different

In case of emergency, whether knowing how to apply first aid or not really ________ in matters concerning wounds like swollen wrists, broken arms, burns, cuts, and so on.

 In case it thunders, we’d better _____________ the electricity at once and turn off the TV.