The great trouble he _____ to show us how to run the machine _____ him completely tired out.

A.takes / makes
B.took / made

填哪个？

一般现在时的用法

1) 经常性或习惯性的动作，常与表示频度的时间状语连用。
　 时间状语： every…, sometimes,　at…, on Sunday
　 I leave home for school at 7 every morning.

2) 客观真理，客观存在，科学事实。
　 The earth moves around the sun.
　 Shanghai lies in the east of China.
3) 表示格言或警句中。
　 Pride goes before a fall.　骄者必败。

　 注意：此用法如果出现在宾语从句中，即使主句是过去时，从句谓语也要用一般现在时。
例：Columbus proved that the earth is round..

4) 现在时刻的状态、能力、性格、个性。
　 I don't want so much.
　 Ann Wang writes good English but does not speak well.

所以一般现在时用在这里不合适，应用一般过去时态。