问题
选择题
The village is ________ on all sides by green mountains, which is rich in natural resources.[ ]
A. surrounded
B. covered
C. divided
D. depended
答案
答案:A
The village is ________ on all sides by green mountains, which is rich in natural resources.[ ]
A. surrounded
B. covered
C. divided
D. depended
答案:A
下表列出了几种物质中的声速.
几种物质中的声速(m/s)
空气(15℃) 340 空气(25℃) 346 软木 500 煤油(25℃) 1324 蒸馏水(25℃) 1497 | 海水(25℃) 1531 铜(棒) 3750 大理石 3810 铝(棒) 5000 铁(棒) 5200 |
①______;
②______;
③______.