She won't open the door, unless she knows who it is
If you painted the walls white, the room would be much brighter
If your brother had driven more carefully, the accident wouldn't have happened
I shouldn't have believed it if I hadn't seen it with my own eyes
Ice turns to water if you heat it
If he reads in bad light, he will ruin his eyes
I could tell you what this means if I knew Chinese
If she had worn her raincoat, she wouldn't have got wet