钻井液固相含量对钻井速度和钻头消耗量都有严重影响，因此，应控制固相含量，一般采用固相含量低于（）%的低固相钻井液。
参考答案：4
“When my husband died five years ago，__________ was difficult to go from ‘we' to ‘me'，”said Joe Kita to us.
A．I
B．that
C．it
D．which
我国对存管后的证券实行非流动性制度，对股权、债权变更引起的证券转移，签发实物证券予以划转。( )
