表面曲率对材料蒸气压、溶解度和熔化温度等物理性质有着重要的影响。固体颗粒越小，表面曲

男性，50岁。咳嗽伴声音嘶哑3个月，右锁骨上窝触及一个肿大的淋巴结，质硬无压痛。提示该患者的诊断可能是（）

A.喉炎

B.肺癌

C.胃癌

D.鼻咽癌

E.肺结核

由于冷冻食品的过程消耗能量，因此很多人使他们的电冰箱保持半空状态，只用它们贮存购买的冷冻食品。但是半空的电冰箱经常比装满的电冰箱消耗的能量更多。

下面的哪项，如果正确，能最好地解释上面描述的明显的矛盾？（）

A．冰箱中使一定体积的空气保持在低于冰点的某一温度比使相同体积的冷冻食品保持该温度需要更多的能量。

B．冰箱的门打开的次数越多，保持冰箱的正常温度所需的能量越多。

C．当将未冷冻的食品放入冰箱中时，冰箱内的一定体积空气的平均温度会暂时升高。

D．通常保持冰箱半空的人可以使用比该冰箱体积小一半的冰箱从而很大程度地削减能耗。

E．只有当冷空气能够在冰箱的冷冻室里自由循环时，电冰箱才能有效地运行。

Katch Ltd is a small private company. Although there are three members of its board of directors, the actual day-to-day running of the business is left to one of them, Len, who simply reports back to the board on the business he has transacted. Len refers to himself as the managing director of Katch Ltd, although he has never been officially appointed as such.Six months ago Len entered into a contract on Katch Ltd’s behalf with Mo to produce some advertising material for the company. However Katch Ltd did not wish to proceed with the advertising campaign and the board of directors have refused to pay Mo, claiming that Len did not have the necessary authority to enter into the contract with him.Required:Analyse the situation with regard to the authority of Len to make contracts on behalf of Katch Ltd and in particular advise whether or not Katch Ltd is liable to Mo. (10 marks)

持握手枪运动以及不向目标射击时，食指应当处在（）。

A.扳机护圈的外面

B.扳机上

C.握柄上

D.扳机护圈的底部

乙炔必须采用能承受（）个大气压的黑色（或绿色）橡胶软管。