Mike's the equal of his sister ____ intelligence is concerned, but he doesn't work hard at all.[ ]

A. as well as

B. as soon as

C. as far as

D. as long as

一般容积大、水深深的湖泊，通常水温的垂向分布有三个层次，上层、中间层(温跃层)和下层，其中溶解氧浓度最高的是( )。

A．上层
B．中间层
C．下层
D．三层溶解氧浓度均接近