()的磨机需进行试运转,试运转正常后可()。
参考答案:新安装或大修后、正式投产
Kunming is a beautiful city ________ flowers and green grass and trees are seen all year round.
A.when
B.where
C.which
D.that
化学工业按生产的产品分类可分为那几大类?