义齿修复的时间应在拔牙后（）
A.1～2周
B.2～4周
C.1～2个月
D.3～6个月
E.6～12个月
参考答案：D
____ doesn't seem to have been much difficulty in solving the problem. [ ]
A. It
B. That
C. There
D. He
在Visual FoxPro中，释放所有的内存变量的命令是______。
