应用洋地黄类药物时应避免与何种药物合用
A．氢氯噻嗪
B．硝酸甘油
C．螺内酯
D．哌唑嗪
E．维拉帕米
参考答案：E
如图，点P是∠AOB的平分线上一点，PM⊥OA，PN⊥OB，垂足分别为M、N，若PM=2cm，则PN=______cm．
The house, ____________is blue, will be used as a library.
A．whose the roof
B．the roof of whose
C．the roof of which
D．which roof
