维管束周木型及外韧型，含晶鞘纤维及油细胞的药材是（）
A.甘草
B.石菖蒲
C.桔梗
D.黄芪
E.天麻
参考答案：B
Not only the workers but also the machine ____ not there.
A．are
B．were
C．is
D．has
The Senate won the vote by a large margin.
