设a=′′a′′，b=′′b′′，c=′′c′′，d=′′d′′，执行语句x=IIf（（ad），′′A′′，′′B′′）后，x的值为（　　）。

简述EDTA与金属离子配位反应的优点。

直接与金属离子配位的EDTA型体为（）。

Project（71）is an uncertain event or condition that，if it occurs，has a positive or a negative effect on at least one project objective，such as time，cost，scope，or quality．

Project ______is an uncertain event or condition that，if it occurs，has a positive or a negative effect on at least one project objective，such as time，cost，scope，or quality．

● Project（71）is an uncertain event or condition that, if it occurs, has a positive or a negative effect on at least one project objective, such as time, cost, scope, or quality.（71）

It will be a relief over the death of a friend or a relative if the friend or relative dies from ______.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

EDTA分子中有六个配位基，而且带电荷高，能与金属离子形成络合比为1：1的络离子，很容易计算。

A mark or place at which a vessel comes under obligatory entry，transit，or escort procedure is know as（）.

能够发生( )反应的金属浸在含有该金属离子的溶液中，才能构成金属一金属离子电极。

能够发生( )反应的金属浸在含有该金属离子的溶液中，才能构成金属-金属离子电极。