A:乌拉尔山脉
B:里海
C:尼罗河
D:土耳其海峡
—They went to the hospital to______________ the sick kids.
“山环水绕,沃野千里”描述的是华北平原的山河大势.(判断对错)
已知函数fx=lnex-e-x2,则fx是( )