沥青材料在生产、使用过程巾，受到热、光、水、氧气和交通荷载等外界因素的作用而逐渐变硬

His wife is in bad condition now and he has to_____ a smiling face though heavy-hearted in the company.[ ]

A. give

B. offer

C. prefer

D. present

下列命令中，哪个命令是Java的API文档生成器

A．float f = 11.1；

B．double d = 5.3E12；

C．float d=3.14f；

D．double f = 11.1E10f；

The little boy is dirty from head to foot because he ___ in the mud all morning.        

A．has played

B．is playing

C．has been playing

D．was playing

塞班手机如何查看版本信息？

付款人开户行收到收款人开户行寄来的第三、四、五联托收凭证及有关债务证明后，对误寄本行的托收凭证如何处理？（）

A.及时转寄正确的付款行，并将情况通知收款人开户行

B.一律注明原因退回原托收行

C.专夹保管相关凭证，不做任何处理

D.直接入账