were (虚拟语气）
这栋建筑看起来就像要倒塌了似的
如果说话人觉得真有倒塌的可能,便用陈述语气,填 is
请在客户端右上角评价点“满意”即可,有可能，还是虚拟语气啊，有没有什么例子It looks as if a shower is coming up. 看样子要下阵雨。 He looks as if he were a little disappointed. 他看起来有点失望。(其实没有失望）