四川盆地油气勘探中，经实践经验证明（）的构造油气富集和保存条件均较理想。
A.褶皱强度大
B.褶皱强度适中
C.褶皱强度弱
参考答案：B
She was always ______, even when things were at their worst.
A．attractive
B．optimistic
C．pessimistic
D．frightened
正常成人QRS波群的时限大多数为
A.0.08～0.12s
B.0.06～0.08s
C.0.08～0.Z0s
D.0.06～0.10s
E.0.08～0.11s
