国际长途的优惠幅度为（）。
A.8折
B.6折
C.5折
D.7折
参考答案：B
She had just finished her homework _____ hermother asked her to practise playing the piano yesterday. [ ]
A. when
B. while
C. after
D. since
胰腺手术后应该采用（）。
A.肠内营养
B.完全肠外营养
C.经口膳食
D.静脉营养
E.鼻饲营养
