根据下面资料，回答21-35题
Mrs．McTavish looked out．"It's a lovely day．Would you like to go for a walk in the park"Her children21with excitement．
"Before we go, you need to follow some rules．Everyone must22hands and stay close to me．You can' t23anywhere by yourself．Can you all do that"
All four24they would．As they walked down the street, Fiona said,"I want an ice lolly(冰棍), Mummy．Can we have some"
"You can if you follow the rules," answered Mrs．McTavish．
The park is just around the corner．The children ran off to25After a while, when Mrs．McTavish looked up she couldn' t see Jock．"Fiona, where' s Jock"
"I don' t know, Mummy．He' s not here26," said Fiona．
The others hadn' t27Jock either．Mrs．McTavish had to gather her children together and walk
around the park28for him．She found him sitting near the ice lolly man．"Jock ! What are you doing
here I couldn' t29you．"
"Mummy, I want an ice lolly, "Jock whispered．
"You can't have one now30you didn't follow the rules．"Mrs．McTavish31one for each of the other children and they licked (~,) them all the way home．Jock cried．When they32home she talked to Jock．"Mummy has four children．I must have rules so I can33an eye on you
and know you' re34．"Jock said he was35and he would follow the rules from then on．
第（23）题选
词义辨析题。你们不能独自去任何地方。meet会面；lie躺；drive开车；g0去。故本题选D。
把10gMgCl2和MgSO4的混合物溶于适量水中，滴加2mol／L的BaCl2溶液至沉淀完全，共消耗BaCl2溶液25mL。求混合物中MgCl2和MgSO4的质量各是多少克
固定在匀强磁场中的正方形导线框abcd，各边长为1．其中ab是一段电阻为R的均匀电阻丝，其余3边均为电阻可忽略的铜线。磁场的磁感应强度为B，方向垂直纸面向里。现有一与ab段的材料、粗细、长度都相同的电阻丝PQ架在导体框上，如图所示。PQ以恒定速度方向如何
一小物块以速度v0=10m／s沿光滑地面滑行，然后沿光滑曲面上升到顶部水平的高台上，并由高台上飞出，如图所示。问当高台的高度h多大时，小物块飞行的水平距离最大这个距离是多少(g=10m／s2)
某晶体盐的水溶液呈浅绿色，在此溶液中通入氯气，溶液变为棕黄色，把所得棕黄色溶液分成两份：一份加入KSCN溶液，溶液变深红色；另一份加入BaCl2溶液，产生不溶于稀HNO3的白色沉淀，则该晶体盐的化学式是_______。
欲除去乙烷中的乙烯，可将混合气体通过盛有_______的洗气瓶；欲除去乙炔中的硫化氢，可将混合气体通过盛有_______的洗气瓶。
浓硝酸常盛装在棕色瓶中，且贮放在冷暗处，原因是_______，
碳酸氢钠溶液和烧碱溶液反应的离子方程式为_______。
常温下，氨水中存在的离子有_______。
在酸或碱存在的条件下，甲酸甲酯跟水发生水解反应的化学方程式为_______。
有下列几种气体：H2、O2、HCl、NO、NH3、CH4，其中通常情况下能用来和水做“喷泉”实验的是_______。
