关于Ig高变区的叙述哪些是正确的（　）

A:氨基酸组成与排列顺序具有更高的变化程度 B:在结构上与抗原决定簇互补 C:由高变区和骨架区组成 D:是Ig分子独特型决定簇主要存在部位 E:H链与L链各有四个高变区

关于Ig的描述，正确的是

A:具有抗原性 B:IgD构成的免疫复合物可通过Clq激活补体 C:IgM中含分泌片 D:Ig有K和λ两类重链 E:可被胃蛋白酶水解成Fab和Fc段

关于Ig分子的论述，哪一些是正确的？（）

A:基本结构为四肽链结构组成的单体 B:一个天然Ig分子轻链的型总是相同的 C:同一类Ig分子C区相同而Ⅴ区可以不同 D:Ig单体可以通过J链聚合成多聚体 E:Ig单体的抗原结合价是2价

正常人尿液中Ig含量很少

尿液中检测到那种Ig升高，说明肾小球滤过膜损伤严重

A:IgG B:IgA C:IgM D:IgD E:IgE

Which of the listed pressure control valves would be used to establish the maximum operating pressure of a hydraulic system?

A:Pressure-reducing valve B:Unloading valve C:Counterbalance valve D:Pressure-relief valve

If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump _____.

A:capacity will increase B:capacity will decrease C:suction pressure will increase D:suction pressure will decrease

Low compression pressure in a diesel engine may be the result of ________.

A:insufficient fuel supply due to fuel pump valves sticking or leaking B:excessive mechanical clearance between the piston crown and cylinder head C:excessively worn fuel pump plunger D:excessive exhaust back pressure

A substantial increase pressure could be an indication of a/an _____.

A:worn cylinder liner B:faulty cylinder relief valve C:excessive lube oil pressure D:excessive scavenge air pressure

In terms of pressure and temperature in the refrigerant in the compressor, what happens to the primary? .

A:its pressure and temperature are both lowered B:its pressure and temperature are both raised C:its pressure is lowered and its temperature is raised D:its pressure is raised and its temperature is lowered