We must______ that the experiment is controlled as rigidly as possible.A．secureB．ensureC．a

We must______ that the experiment is controlled as rigidly as possible.

A．secure

B．ensure

C．assure

D．issue

正确答案：B
解析：此题考查动词词义。ensure确保。issue为无关干扰词，发行：分配。