中途测试中,钻杆丝扣应涂以润滑脂,并按规定扭矩上紧各道丝扣。
参考答案:错
解析:中途测试中,钻杆丝扣应涂以高温密封脂,并按规定扭矩上紧各道丝扣。
妊娠期牙龈炎为
A.牙龈卟啉单孢菌B.粘性放线菌C.伴放线放线杆菌D.梭形杆菌和螺旋体E.中间普氏菌 下列与牙周病最为密切的致病菌
A new club in our school at the beginning of this year and now it has many members.
A.starts
B.is started
C.has started
D.was started