第23题: [填空题]The calculations would have been useless when they were worked out ______ (如果当时没有电脑的话). 参考答案:had it not been for the computer/if it had not been for the computer 答案解析:[考点] ①非真实条件句中的虚拟语气【考频:6】;②非真实条件句中的倒装【考频:5】。
[精析] ①根据句意,本句是与过去事实相反的虚拟语气,缺少条件状语从句,所以从句的谓语动词应使用had+过去分