17.____your brother or you to blame for the broken TV set?
A.Be B.Are C Is D Were
答案:C
选煤厂直接从事生产建设的职工,必须进行强制的安全培训。未经安全培训合格的职工,不得上岗作业。
弹性联轴器在风力发电机组中的特点和重要性?