油毡瓦屋面基层应铺设一层沥青防水卷材垫毡。油毡瓦铺设，应不少于______。A．4层

阅读下面短文，用括号内所给动词的适当形式填空 (必要时可加情态动词或助动词)。

Many of us Chinese are Yao Ming’s fans. Of course we all know he 1     ( retire ) for several months . Yao made farewell(告别) conference Wednesday. He said he  2  (force )to make this decision by a series of foot and leg injuries. Yao played eight seasons in the NBA.

“Today is an important day for me and   3  (hold) a special meaning for both my basketball career and my future,”Yao said. “ I    4  (think) about my future for a long time. Today I am announcing a personal decision,   5  (end ) my career as a basketball player and officially retire. But one door is closing and another one   6  (open).’’

Yao said he   7   ( return) to work with his former Chinese team, the Shanghai Sharks, with the possibility of    8  (become) general manager. He already   9  (own) the club and wants to contribute more. He thanked a lot of people — his family, former coaches, even players like Shaquille O’Neal — “for making me a better player.’’

Rockets(火箭队) general manager Daryl Morey was among those attending the farewell conference Wednesday. “I would be sorry if I wasn’t here.” “It’s a big moment,’’ Morey added. “Yao had a sense of humor, a great attitude and sense of responsibility. I hope we 10  (continue) his culture in the NBA.’’

新疆的西瓜比我们四川的甜，决定这一现象的主要因素是（　　）

A．温度

B．阳光

C．水分

D．湿度

可逆自动调心托辊的工作原理是什么？

男性，27岁，林业工人，伐树时电锯失控，左前臂完全离断，当即转院，同时带走的离断肢体，必须干冻冷藏保护，冷藏温度保持在

A．-41℃
B．-2℃
C．0℃
D．2℃
E．4℃

甲现有一房屋欲出租给乙，丙为阻止甲的出租行为，称其愿出高价租用甲的房屋，致使甲乙之间的租赁合同没有订立。随后，丙借故说不租用甲的房屋。此时，甲可以要求丙承担( )。

A．擅自解除合同的责任
B．违约责任
C．缔约过失责任
D．合同未成立的责任