急性胰腺炎时，最有诊断意义的血清酶是 ( )
A．氨基转移酶B．碱性磷酸酶C．肌酸激酶D．淀粉酶E．酸性磷酸酶
参考答案：D
Either you or one of your students ________ to attend the meeting that is due tomorrow.
A．are B
B．is
C．have
D．be
He fell ________ the bike yesterday. [ ]
A. down
B. up
C. on
D. off
