Stop _____, let's begin our class. [ ]
A. talk
B. to talk
C. talking
D. talked
答案:C
施工合同订立后,发包人有确切证据证明承包人经营状况严重恶化,拒绝支付预付款,这时发包人可行使( )。
A.同时履行抗辩权
B.代位权
C.撤销权
D.不安抗辩权
岩柱厚度与哪些因素有关?