增生性龈炎的直接病因是
A.牙菌斑B.服用药物C.内分泌导致的激素变化D.遗传因素E.全身疾病
参考答案:A
根据括号内的汉语提示,完成句子。
1. Tomatoes are healthy, but I don't like __________ (它们).
2. After getting up, he usually __________ (刷) his teeth.
3. His subject is only running __________ (到处) with me.
4. Sally is so __________ (疲倦) that she really wants to go to bed earlier.
5. My birthday is in December. It's the __________ (第十二) month in a year.
6. I can't find my socks anywhere, because they are __________(在…下面) my bed.
下列关于登高焊割作业的安全措施,哪些是正确的?()
A.登高焊割作业所使用的工具、焊条等物品应装在工具袋内,防止操作时落下伤人
B.不得在高处向下抛掷材料、物件或焊条头,以免砸伤、烫伤地面工作人员
C.禁止把焊接电缆、气体胶管及钢丝绳等混绞在一起,或缠在焊工身上操作
D.登高焊割作业应使用带有高频振荡器的焊接设备
E.登高焊割作业结束后,必须仔细检查工作地及下方地面是否留有火种,确认无隐患后,方可离开现场