初级井控依靠适当的钻井液密度来控制住地层压力。
参考答案：对
(2013·菏泽模拟)The building project ________ next year is not easy ________ in time.
A．being carried out; to complete
B．carried out; to be completed
C．to be carried out; to complete
D．to be carried out; to be completed
单根牙牙周膜的附着面积在哪个区域最大（）
A.牙颈部
B.根尖部
C.根中1/3处
D.根尖1/3处
E.根上1/3处
