在进行钢筋混凝土实心板的施工过程中，下列对混凝土骨料最大粒径的要求中正确的是( )。

2021年6月17日，神舟十二号载人飞船发射圆满成功。飞船整个设计、制造、发射等阶段均离不开大量的、精密的科学...

单项选择题2021年6月17日，神舟十二号载人飞船发射圆满成功。飞船整个设计、制造、发射等阶段均离不开大量的、精密的科学计算，而这些计算都依赖于计算机实现，这属于计算机在人工智能方面的应用。
A、正确
B、错误

萃取三角形三个顶点分别表示纯溶质、纯原溶剂、纯萃取剂。 （ ）

单项选择题萃取三角形三个顶点分别表示纯溶质、纯原溶剂、纯萃取剂。 （ ）

根据下面资料，回答21-35题Mrs．McTavish looked out．"It's a lovely d...

单项选择题根据下面资料，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（21）题选