I had no idea what the respiratory system did and I couldn't punctuate a sentence.
我对呼吸系统能做什么一无所知，我也不会给一个句子标上标点符号。
2
Complex sentence: the system shall be able to display the elapsed time for the car to make one circuit around the track within 5 seconds of the lap completion.
复合句：系统应能在车沿跑道绕行一圈后5秒之内显示这一圈花费的时间。
3
Simple sentence: The system shall be able to display the elapsed time for the car to make one circuit around the track.