下列内脏感觉的特点，哪项是错误的
A．感觉迟钝
B．感觉敏锐
C．针刺、切割不引起疼痛
D．牵拉引起疼痛
E．疼痛定位不明确
参考答案：B
有效资产组合曲线是一个由特定投资组合构成的集合，集合内的投资组合在既定的风险水平上，期望报酬率不一定是最高的。 ( )
As a matter of fact, this group of scientists many difficulties to complete the project. [ ]
A. went through
B. got through
C. went up
D. got in
