The main thing is ____ (learn) how to be polite.
Fire is very dangerous. It can ____people. We ____be careful with fire. We mustn't play near fires. We mustn't play with matches. We mustn't ____in the forest. When we see a fire, we must go outside ____,but ____use the lift.
已知∠AOB=80°,以O为顶点,OB为一边作∠BOC=20°,则∠AOC=( )
关于民族文化特色说法正确的是( )