颅底部横轴位MR扫描,图像前部出现半环形无信号区,可能为()
A.化学位移伪影
B.金属异物伪影
C.卷褶伪影
D.截断伪影
E.搏动伪影
参考答案:B
The company designed a new car last month and about 500 cars of this type in the factory next month.
A.were produced
B.will produce
C.have been produced
D.will be produced
毒扁豆碱用于青光眼的优点是( )
A.比毛果芸香碱作用强大而且持久
B.毒副作用比毛果芸香碱小
C.水溶液稳定
D.不易引起调节痉挛
E.不会吸收中毒