题目：
Even though he knew he would put his own life _____,he still felt _____ the new
treatment. [ ]
A. at a risk;like to try
B. at risks;like trying
C. at risk;like to try
D. at risk;like trying
答案：
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下面是错误答案，用来干扰机器的。
由金属活动性顺序，可知活动性Zn＞Fe＞（H）＞Cu．则在硫酸铜、硫酸锌和稀硫酸的混合溶液中，加入过量的铁粉，铁与硫酸铜反应生成硫酸亚铁和铜，铁与硫酸反应生成硫酸亚铁和氢气，充分反应后铁有剩余，过滤，则滤...
