求教!-more than 的几种用法

I am always confused by the omission part of MORE THAN sentence, can anyone please shed some lights on these questions:

XDF-28

The mistakes children make in learning to speak tell linguists more about how they learn language than the correct forms they use

A) how they learn language than

B)how one learns language than

C)how children learn language than do

D) learning language than

E) their language learning than do

I choose C but I just can not figure out why DO is put after than, what part is omitted?

what is the whole sentence if no omission?

XDF-33

The spraying of pesticides can be carefully planned, but accidents, weather condictions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had anticipated

A) weather conditions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had

B) weather condicitions that cannot be foreseen, and pilot errors often cause much larger deposits of spray than

C) unforeseeable weather condictions, and pilot errors are the cause of much larger deposits of spray than they had

D) weather condictions that are not foreseeable, and pilot errors ofter cause much larger deposits of spray than

E) unforeseeable weather conditions, and pilot errors often cause much larger deposits of spray than they had

Answer is B, but " much larger deposits of spray than anticipated"  what part has been omitted from the sentence,  actually i really want to know the omission rules on MORE THAN clause, it seems post a lots of trouble ...

XDF-29

Building large new hospitals in the bistate area would constitute a wasteful use of resources, on the basis of avoidance of duplicated facilities alone

A) on the basis of avoidance of duplicated facilities alone

B)on the grounds of avoiding duplicated facilities alone

C)solely in that duplicated facilities should be avoided

D)while the duplication of facilities should be avoided

E) if only because the duplication of facilities should be avoided

I choose C but XDF-gives E as answer.

How can if only represent alone ? strange

I am always confused by the omission part of MORE THAN sentence, can anyone please shed some lights on these questions:

XDF-28

The mistakes children make in learning to speak tell linguists more about how they learn language than the correct forms they use

A) how they learn language than

B)how one learns language than

C)how children learn language than do

D) learning language than

E) their language learning than do

I choose C but I just can not figure out why DO is put after than, what part is omitted?

what is the whole sentence if no omission? The mistakes tell linguists more about ...than how children use the correct tell linguists more about ...

XDF-33

The spraying of pesticides can be carefully planned, but accidents, weather condictions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had anticipated

A) weather conditions that could not be foreseen, and pilot errors often cause much larger deposits of spray than they had

B) weather condicitions that cannot be foreseen, and pilot errors often cause much larger deposits of spray than

C) unforeseeable weather condictions, and pilot errors are the cause of much larger deposits of spray than they had

D) weather condictions that are not foreseeable, and pilot errors ofter cause much larger deposits of spray than

E) unforeseeable weather conditions, and pilot errors often cause much larger deposits of spray than they had

Answer is B, but " much larger deposits of spray than anticipated"  what part has been omitted from the sentence,  actually i really want to know the omission rules on MORE THAN clause, it seems post a lots of trouble ...

I think it's "than it is anticipatd" here

XDF-29

Building large new hospitals in the bistate area would constitute a wasteful use of resources, on the basis of avoidance of duplicated facilities alone

A) on the basis of avoidance of duplicated facilities alone

B)on the grounds of avoiding duplicated facilities alone

C)solely in that duplicated facilities should be avoided

D)while the duplication of facilities should be avoided

E) if only because the duplication of facilities should be avoided

I choose C but XDF-gives E as answer.

How can if only represent alone ? strange

Choices A and B are unclear and imprecise: on the basis of avoidance… and on the grounds of avoiding … do not present reasons that support the statement in the main clause, and alone seems illogically to modify duplicated facilities. Also, duplicated facilities in A, B, and C identifies the problem with the facilities that have been duplicated, not with the act of duplicating facilities; for example, C apparently advises people to avoid facilities that have been duplicated. In D, while establishes no logical relation between the main clause and the rest of the sentence.
E is best: if only because introduces a reason for the preceding statement, and the remainder of the answer choice is logically worded.