77．Parasitic wasps lay their eggs directly into the eggs of various host insects in exactly the right numbers for any suitable size of host egg．If they laid too many eggs in a host egg，the developing wasp larvae would compete with each other to the death for nutrients and space．If too few eggs were laid，potions of the host egg would decay, killing the wasp larvae．
Which of the following conclusions can properly be drawn from the information above?
(A) The size of the smallest host egg that a wasp could theoretically parasitize can be determined from the wasp's egg-laying behavior．
(B) Host insects lack any effective defenses against the form of predation practiced by parasitic wasps．
(C) Parasitic wasps learn from experience how many eggs to lay into the eggs of different host species．
(D) Failure to lay enough eggs would lead to the death of the developing wasp larvae more quickly than would laying too many eggs．
(E) Parasitic wasps use visual clues to calculate the size of a host egg．
Argument Construction
Situation Parasitic wasps lay their eggs inside suitably sized host eggs．The wasps must be exact about the numbers of eggs they lay in the host eggs．If they lay too many, the wasp larvae have to compete for nutrients and space；if they lay too few, the host egg decays，killing the wasp larvae．
Reasoning What is the best-supported conclusion to be drawn from this information? Approach this question by eliminating first the suggested conclusions that 1ack logical support，and then consider the content and logic of the remaining possibilities．A review of the alternatives seems to rule out four options，so consider and confirm the first．The first sentence of the passage explains that the wasps lay eggs in exactly the right numbers for the size of the host egg．The wasps’ behavior could be examined by comparing different sizes of the host eggs in which wasps have laid different numbers of eggs．It would be possible then to determine the size of the smallest host egg that the wasp could lay its egg(s)in successfully．
A Correct．This statement properly identifies the conclusion that an examination of the wasps’ egg-laying behavior would reveal，at least in theory, the size of the smallest host egg a wasp could lay its egg(s)in．
B The passage is about the parasitic wasps，not about the host insects，so a conclusion．that is about the hosts is not supported．
C The passage does not discuss how the wasps have the ability to lay the right number of eggs，so the conclusion that they learn by experience is not earned．
D The passage does not present any information about the relative speed with which tOO many or too few developing larvae die，so this conclusion is not founded．
E No information in the passage supports the wasps’ use of visual clues，so this conclusion is not
The correct answer is A．
看了解释还是不懂。
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