初入学的儿童，学习兴趣的特点为()A．有选择性但不分化 B．既无选择性又无分化 C．

What is the maximum price an investor should be willing to pay (today) for a 10 year annuity that will generate $ 500 per quarter (such payments to be made at the end of each quarter) , given he wants to earn 12 percent, compounded quarterly（）

A. $11300.

B. $11557.

C. $6440.

当前国外减少或防止塑料废弃物对环境影响的措施可概括为（）。

A.3R和2D

B.3R和1D

C.4R和1D

D.4R和2D

生态学的基本观点应该是生物与（）的辩证统一。

A.人类

B.自然

C.微生物

D.环境

事故应急救援需要通信保障时，事故发生在站内，通信部门应在（）开通电话。

A.60min

B.40min

C.30min

D.20min