下面属于Java关键字的是 ( )
A.NULL
B.IF
C.do
D.goto
参考答案:C
The sports meet __________ be held until next week.[ ]
A. doesn't
B. won't
C. isn't
地幔分为上地幔主要由()类物质组成,下地幔主要由铁镍金属氧化物和硫化物组成。