1. (2018·全国卷Ⅱ)The Chinese Ministry of Agriculture finds that between 2005 — when the government ________ (start) a soiltesting program that gives specific fertilizer recommendations to farmers — and 2011, fertilizer use dropped by 7.7 million tons.
解析：started 根据破折号前的内容可知，此处说的是2005年发生的事情，应用一般过去时。
2．(2017·全国卷Ⅱ)Later, engineers ________ (manage) to construct railways in a system of deep tunnels (隧道), which became known as the Tube.
解析：managed 由语境可知，此处讲的是发生在过去的事情，所以用一般过去时，主语engineers和manage之间是主动关系，故填managed。
3．(2017·全国卷Ⅲ)Sarah says, “My dad thinks I should take the offer now. But at the moment, school ________ (come) first.”
解析：comes 此句是直接引语，陈述客观事实，根据前面句子的谓语可知，动词come应该使用一般现在时。
4．(2017·6月浙江高考)Pahlsson and her husband _______ (search) the kitchen, checking every corner, but turned up nothing.
解析：searched but后面的“turned up nothing”使用了过去时，search是与之并列的谓语动词，根据语境可知，此处描述的是过去发生的行为，故要用一般过去时。
5．(2016·四川高考)However, it stayed with her and learned about the ways of the forest.Then, after two and a half years, the mother ________ (drive) the young panda away.
解析：drove 此处讲过去发生的事，所以用一般过去时且为主动形式，故用drive的过去式drove。
6．(2015·全国卷Ⅱ)This cycle ________ (go) day after day：The walls warm up during the day and cool off during the night and are thus always a timely offset (抵消) for the outside temperatures.
解析：goes 此处指这种循环日复一日地不断持续下去，由冒号后内容的时态可知这种情况是客观性陈述，故用一般现在时。
7．(2014·全国卷Ⅰ)In 1969, the pollution was terrible along the Cuyahoga River near Cleveland, Ohio. It ________ (be) unimaginable that it could ever be cleaned up.
解析：was 根据“In 1969, the pollution was terrible”可知，此处叙述的是过去发生的事情，因此用一般过去时，由于主语是It，因此此处谓语用was。
