单项选择题
Our family()not to exchange Christmas gifts this year.
A.has agreed B.had agreed C.have agreed D.agrees
单项选择题 门静脉高压食管曲张静脉破裂出血最有效的止血方法是()。
单项选择题 SPECT的系统分辨率等于()
单项选择题 () what would happen, none of them could find a way out.