托辊作用是什么？
参考答案：
支承胶带减少运行阻力，并使胶带垂度不超限，以保证胶带平稳运行。
—I hear that Mr King was robbed of his new mobile phone on his way home last night.
—______! He shouldn't go home so late.[ ]
A. Oh, never mind
B. What a pity
C. You're welcome
D. Sorry to hear that
In order to make our city green, ______.[ ]
A. it is necessary to have planted more trees.
B. many more trees need to be planted.
C. our city needs more trees.
D. we must plant more trees.
