有关左房黏液瘤,正确的是()
A.好发于左心耳
B.是心脏内最常见的恶性肿瘤
C.可出现肺循环栓塞表现
D.手术切除后不会复发
E.以上都不是
参考答案:E
Everyone passed the exam.It _________ difficult.
A.can’t have been
B.must have been
C.couldn’t be
D.might have been
判断直导体和线圈中电流产生的磁场方向,可以用右手螺旋定则。( )