企业发生销售退回而退回货款时, 应以退货发票作为付款的原始凭证。( )
参考答案:错
Hello! I'm glad to see you here. When _____ you _____? [ ]
A. did, arrive
B. will arrive
C. have, arrived
D. are arriving
牙槽嵴修整术最好在何时进行()
A.拔牙后2周
B.拔牙后6周
C.拔牙后1个月
D.拔牙后2个月
E.拔牙后3个月