"水火既济"相关的两脏是（）
A.心与肺
B.心与脾
C.心与肾
D.肝与脾
E.肝与肾
参考答案：C
x2-______=x6，x2-x3-x6÷x=______．
—We really ______ the umbrellas. Look! It has cleared up.
—Well, we might as well take one with us, just in case. [ ]
A. don't need to bring
B. needn't have brought
C. didn't need to bring
D. need to bring
