【判断题】配位滴定中,与EDTA反应较慢或对指示剂有封闭作用的金属离子一般应采用返滴定法进行测定。( )
【判断题】目前国内改革和发展中会衍生出“政治文化厌忘情结”。( )
【多选题】配位滴定中,在什么情况下不能采用直接滴定方式?
A.
待测离子与EDTA配位反应速率较慢,或能封闭指示剂,如Al3+、Cr3+等
B.
滴定反应缺乏变色敏锐的指示剂,如Ba2+、Sr2+等的滴定
C.
待测离子与EDTA不能形成配合物或形成的配合物不稳定,如碱金属
【单选题】____ of plastics, the machines are easy to carry.
H.
We often provide our children with toys, footballs or basketballs, that all children like these things.
J.
think K. to think L. thought
【单选题】These toys are made of tough plastic.
A.
difficult to do or deal with, and needing a lot of effort and determination
B.
able to live through difficult or severe conditions
C.
difficult to break or damage
E.
difficult to cut or eat
【单选题】下列哪个检查比率不属于客户信用额度中所需要检查的比率信息?
【简答题】完形填空。 There are times in our lives when we remember. Remembering the good things of __ 1__ is a most precious (宝贵的) time; these memories are __ 2__ in the corner of my mind. When I was four years old,...