设函数y=y（x）由参数方程
Thedestructionofthetwintowers_________shockandangerthroughouttheworld．
Ishallneverforget________(meet)thelatePremierZhouduringhisinspectionofourfactory.
Constructionoftherailwayshelpedtodevelopthenational_______ofTanzaniaandZambia.
二维随机变量(X,Y)在D=（x，y）0<y<1-x2上服从均匀分布，求Z1,Z2联合分布。
