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【多选题】
In an experiment of Cr(VI) removal by an ion-exchange technique, there were 5 levels of factor pH, pH=3.0, 5.0, 7.0, 9.0, 11.0. Under each pH level, the Cr(VI) removal treatment was triplicate, that is to say, conducted 3 times. Which below may be the correct expression about this experiment?A.
Mean square (MS) can be expressed as the sum of squares divided by the degree of freedom.
B.
The total degree of freedom is 14.
C.
The degree of freedom among groups is 4.
D.
The degree of freedom of error is 10.
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【判断题】Teachers benefits from practice even if they do not keep on reflecting on what they have been doing.
A.
正确
B.
错误
【单选题】Suppose society wants to increase the number of teachers in society but doesn't want to pay teachers any more in salary and benefits. This could only occur by
A.
it less expensive to become a teacher, perhaps by offering subsidies to college tuition.
B.
increasing the income of student parents.
C.
computers more powerful.
D.
it more expensive to become a teacher, perhaps by raising college tuition rates.
【简答题】半殖民地半封建社会的主要矛盾及其关系。
【单选题】Some teachers enthusiastically _______ the benefits to be gained from educational software.
A.
expose
B.
espouse
C.
estrange
D.
exploit
【判断题】Teachers benefits from practice even if they do not keep on reflecting on what they have been doing.
A.
正确
B.
错误
【单选题】We'll send our homework ____ our teachers ____ e-mail . [ ]
A.
for ; on
B.
to ; by
C.
to ; on
D.
for ; from
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