问题
选择题
The trouble with such resources as coal, oil and gas ______ that they are not renewable.
A．was
B．are
C．have been
D．is
答案
答案：D
题目分析：句意：象煤，油和气这样的资源问题是它们不是可再生的。这句话是客观事实，所以用一般现在时，又因为主语是the trouble所以谓语用单数，所以选D。