分离酸性皂苷和中性皂苷，首选（） A.胆甾醇沉淀法 B.铅盐沉淀法 C.明胶沉淀法

下列词语中，没有错别字的一组是（   ）

A．部署笔杆子要言不烦陈词滥调

B．慈祥摄相机唉声叹气浅尝辄止

C．急躁露马脚顶礼膜拜出奇不意

D．喧染发帖子情投意合殚精竭虑

Andrew is a farmer, who has had his tractor repaired by Ben. He had explained to Ben that he needed the engine in perfect working order to harvest his seasonal crops. As a result of Ben’s poor workmanship, the tractor broke down a month later. Although Andrew returned the tractor immediately to Ben for repairs, Ben only repaired the tractor a month later. By that time, a portion of Andrew’s crops to the value of R80,000 (which was still on the fields) was lost.Required:Discuss whether Andrew will be entitled to claim damages from Ben for breach of contract. (10 marks)

对于磷酸二酯酶抑制药，下列说法正确的是

A．发挥正性肌力作用
B．适合长期治疗
C．收缩血管
D．米力农不属此类药
E．长期应用不会引起室性心律失常

手动防喷器具有结构简单、（）、安装使用方便的特点。

A、体积大

B、体积小

C、大而灵活

D、小而笨重

某高层框架结构，抗震等级为二级，考虑地震作用组合时，梁端弯矩设计值为：左端M_b¹=273.1kN·m，右端=448.5kN·m，与地震作用组合时的竖向荷载作用下梁端剪力设计值V_GB=128.6kN·m，梁的跨度l_n=6m，计算框架梁的剪力设计值V_b（kN），（）项是正确的。

A．254.88

B．260.89

C．272.9

D．253.40