基层工会换届选举的筹备工作由（）负责。
A.工会 * *
B.上届工会委员会
C.筹备组
D.指定的人员
参考答案：B
By the end of last month, we had produced _____ as we did last year.
A．as twice many cars
B．twice many as cars
C．twice as many cars
D．as many cars twice
预防牙周疾病提高宿主抵抗力的措施是（）。
A.降低牙尖高度和斜度
B.去除不良修复体
C.消除食物嵌塞
D.去除充填物悬突
E.合理补充营养素
