—I was asked to attend the meeting before eight.—Oh, you________. I'm sorry for not telling you that we have changed the plan.
A:must
B:can't
C:may
D:needn't
为了我们的生活更美好,我们要美化大自然。下列是美化自然的行为是( )
①爱护身边的一草一木,不践踏草坪 ②积极参加植树造林活动
③在风景区旅游,不乱仍垃圾,不乱写乱画 ④利用休息日,到风景区清除垃圾