题目

El Nifio, a Spanish term for “the Christ child”, was named by South American fisherman who noticed that the global weather pattern, which happens every two to seven years, reduced the amount of fishes caught around Christmas. El Nifio sees warm water, collected over several years in the western Pacific, flow back eastwards when winds that normally blow westwards weaken, or sometimes the other way round.The weather effects both good and bad, are felt in many places. Rich countries gain more from powerful Nifio, on balance, than they lose. A study found that a strong Nifio in 1997 helped Ame我们吃西瓜时，会有许多甜汁流出，这种汁液主要存在于（ ）A.液泡内B.细胞核内C.细胞壁上D.细胞膜上