266. At first he did not realize that he had succeeded in making a computer that ran on solar power(太阳能). “Realize” in the sentence means “___________”

A．understand

B．get to

C．reach

D．come true

60岁男性，无诱因出现尿频、尿急、排尿费力，夜间为重，尿常规未见异常，下一步首先应做的检查是（）

A、双肾B超

B、腹部平片

C、尿培养

D、前列腺B超

E、前列腺液检查