Frank _________work to do. [ ]
A. has many
B. has much
C. have a lot
D. have a lot of
答案:B
变压器在()时效率最高。
A、铜损等于铁损时
B、铁损大于铜损时
C、铁损小于铜损时
D、铜损=2×铁损
下列哪项不是原发性高血压患者的心理特点()
A.攻击
B.焦虑
C.猜疑
D.偏执
E.紧张