题目

如图，∠1＝10°，∠2＝∠3＝∠4＝∠5＝20°，则∠6＝＿＿＿°  答案：50解析:因为∠2＝∠3＝∠4＝∠5＝20°，∠1＝10°，所以∠7=90°，∠6=180°-90°-∠4-∠5=50°  ---Don't put the waste on the ground.                 ---Oh, I'm very sorry. I ________ the dustbin there. A．don't see B．isn't seeing C．didn't see D．haven't seen