钻井液的主要化学特征是()
A、一般比较浑浊;
B、一般比较清澈;
C、粘稠状;
D、氯离子含量低;
E、含较多固体杂质;
F、固体杂质少。
参考答案:A, C, D, E
--- Everybody is playing outside. Can I join them, Mom?
--- _______ Not until you have finished practicing the piano.
A.Why not?
B.Will you?
C.I hope so
D.I’m afraid not.
时代赋予当代青年的崇高使命是 [ ]
A.崇尚科学
B.振兴中华
C.热爱劳动
D.自主创新