“ since a concurrent sharp decline in populations of seals and sea lions is believed to have been caused by disease”,这句的concurrent是关键,海豹和海狮的下降和otter的下降是同时发生的,所以给A选项创造了可能。
so as to/ so that / enough to A. so…as to 的结构表达了一种目的,而so…that 表达了consequence,语义上是有区别的,这里描述的是自然现象,用表目的的as to不是太合适——充满水以为了获得液体的特性 vs 充满水导致其获得了液体的特性,明显后者比较好;
z=1,x=0.5,y=-0.5,怎么满足条件1啊?1 > 0.5-0.5+1?