题目

把0.05mo1Na0H 固体分别加入下列100ml 液体中，溶液导电能力变化不大的是                                                         (   )A. 0.5 mol/L 氢氟酸    B.0.5mol/L 盐酸C. 0.5mol/ L 醋酸        D．自来水  答案：B解析:略  综合填空。从方框中选择适当的词，并用其适当形式补全短文。if, until, but, make, at, accidents, be, green, right, redThis is a street crossing. There are red and green traffic lights 【1】 each corner. Drivers must 【2】 careful to watch them.When the traffic light is 【3】 , the cars may go. When the light turns 【4】 , the cars must stop. They must wait（等待） 【5】 the red light turns green. Then they can go on. Sometimes the drivers want 【6】 a right turn or a left turn. They can make a 【7】 turn when the light is green or red. 【8】 they shouldn’t drive too fast. 【9】 they want to make a left turn, they must wait until the traffic light is green. There may be 【10】 if drivers don’t obey the traffic rules. All of the drivers should be very careful when they are driving on the road.