当年所有进款用于需要者并给予支付的社会保障模式是（）
A.完全积累制
B.部分积累制
C.现收现付制
D.后收后付制
参考答案：C
Sorry, I am too busy now. If I ________ time, I would certainly go for an outing with you. [ ]
A. have had
B. had had
C. have
D. had
景观生态学中斑块形状有( )。
A．圆形
B．多边形
C．长条形
D．半岛形
E．环形
