题目

 Constant practice has erased my accent to a point ______ people think I'm a native speaker. A. that                         B. which                      C. in which                  D. at which 答案：D19．通过下列实验可以得出的结论，其中不合理的是（　　）A．甲实验证实了宇宙正在膨胀中B．乙实验可以探究水的运输部位是茎的木质部C．丙中铁钉表面覆盖一层红色的物质可以说明铁的金属活动性比铜强D．丁中的米勒模拟实验支持了生命物质可由非生命物质转化而来的可能