在反应：Fe2(SO4)3+6KSCN2Fe(SCN)3+3K2SO4达到平衡后

Being a parent is not always easy and being the parent of a child with special needs often carries with _____extra stress.

A．it

B．one

C．them

D．him

基本的呼吸节律产生于

A．脊髓

B．延髓

C．脑桥

D．中脑

E．大脑

Luckily, we’d brought a road map, _________ we would have lost our way.

A．without it

B．with that

C．without which

D．without that

土地登记代理的基本原则有( )。

A．无偿

B．保密

C．公平公正

D．平等自愿

E．诚实信用

直流电动机采用调压调速时，电机转速只能往低调，属恒功率调速。