【C2】A．changeB．decisionC．reductionD．relation

A．changeB．observeC．improveD．meet

【C13】A．descentB．inductionC．reductionD．decline

【C4】A．changeB．alterC．varyD．differ

【C10】A．changeB．alterC．varyD．contrast

【C6】A．changeB．mistakeC．differenceD．mark

【C6】A．changeB．notesC．checksD．bills