Every possible means _____ to prevent air pollution,but the
Every possible means _____ to prevent air pollution,but the sky is still not clear. A is used B are used C has been used D have been used 要详解,谁详细明了谁拿分.别选错哦
Every possible means have been used to prevent air pollution,but the sky is still not clear. 每一个可能的方法都被用来防止空气污染了,但是天空还是无法晴朗。 选d因为不可能是a或者c因为means是复数。而b又不是被动语态,所以只能是d