单句语法填空
1．(2019·重庆第一次质量抽测)If the new safety system (bring) into use, the accident would never have happened.
had been brought 解析：句意：如果新的安全系统已经投入使用，事故就不会发生了。根据句意、句子结构以及主句中的would never have happened可知，句中If引导的是虚拟条件句，且表示与过去的事实相反的假设，故从句时态应用过去完成时。
2．(2019·浙江杭州地区七校模拟)When you phoned me, I was having a meeting; how I wish I (answer) your call.
had answered 解析：句意：当你给我打电话的时候，我正在开会。我多么希望我(之前)接了你的电话。wish后的从句中用虚拟语气，根据句意可知是对过去情况的虚拟，所以谓语动词用had done形式。
3．(2019·安徽江淮十校联考)As the deadline is drawing near, no one leave with his own work uncompleted.
shall 解析：句意：因为截止日期即将到来，不完成工作，任何人不许离开。shall用于第三人称陈述句中，表示命令、警告，符合句意。
4．(2019·东北三校联考)The order came that the medical supplies (send) to the earthquakestricken area soon.
(should) be sent 解析：表示建议、要求、命令等名词，如：suggestion, order, request, advice等后接的表语从句、同位语从句中谓语动词用(should＋)动词原形。
