Fire can____ down a lot of trees. It can____ people, too. We must be____with fire. We mustn't____ in the forest. We mustn't play____ fires at home. We mustn't play with matches either.
下列是某同学进行过滤操作时的一些做法,其中错误的是( )
如图,∠1=∠2,∠3=40°,则∠4等于( )