In order to withstand tidal currents, juvenile horseshoe crabs frequently burrow in the sand. Such burrowing discourages barnacles from clinging to their shells. When fully grown, however, the crabs can readily withstand tidal currents without burrowing, and thus they acquire substantial populations of barnacles. Surprisingly, in areas where tidal currents are very weak, juvenile horseshoe crabs are found not to have significant barnacle populations, even though they seldom burrow.

Which of the following, if true, most helps to explain the surprising finding?

A. Tidal currents do not themselves dislodge barnacles from the shells of horseshoe crabs.

B. Barnacles most readily attach themselves to horseshoe crabs in areas where tidal currents are weakest.

C. The strength of the tidal currents in a given location varies widely over the course of a day.

D. A very large barnacle population can significantly decrease the ability of a horseshoe crab to find food.

E. Until they are fully grown, horseshoe crabs shed their shells and grow new ones several times a year.[E]

这T 找不到思路的感觉 读完找不到切如点！就觉得乱乱的一大堆东西！

觉得答案一定和 WEAK TIDAL CURRENT 有关系 就找带这个的答案！万万没想到答案是E

E 说的是 Until they are fully grown, horseshoe crabs shed their shells and grow new ones several times a year （是说长大之前啊，还是长大之后啊！直到他们长大，不是说长大之后吗，那不就解释不了了吗！）文章说的是juvenile horseshoe crabs

这是解释矛盾题（或解释现象），要先找到矛盾（或奇怪现象）。

奇怪现象：Such burrowing discourages barnacles from clinging to their shells即一般juvenile horseshoe crabs 会附着 barnacles 。但是， juvenile horseshoe crabs are found not to have significant barnacle populations, even though they seldom burrow（这排除BURROW使它们没有附着barnacle的原因）。所以你要找另外原因解释 found not to have significant barnacle 。E的意思为 juvenile horseshoe crabs （ Until they are fully grown指在他们长大前）一年有几次脱旧壳，长新壳。所以上面的barnacle都给脱掉了，当然没发现 barnacle 。