题目

Students have turned to        English hard because the new English teacher keeps        them to learn it.        A．study; to encourage                      B．studying; encouraging C．study; on encouraging                   D．studying; to encourage 答案：B如图是A、B、C三种物质的溶解度随温度变化的曲线图．请据图回答下列问题：（1）在______℃时，A、C物质的溶解度相等．（2）t2时，A、B、C的溶解度由大到小的顺序是______．（3）要使A物质从它的溶液中析出，宜采用的方法是______（填降温结晶或蒸发结晶）．（4）t3℃时，50g水中最多可溶解A物质______g．