During vacation time time为什么不加s

1.it took the writer three hours to do his homework. 
不对, those took me three hours or more. 不止三个小时.
 2.as the afternoon was hot，i did my work in the evening
不对, as the afternoon was hot,i did my work in the morning. 早上不是傍晚.
 3.the weather was warm and i could do much work 
不对, the weather was hot and i could not do much work.
 4.the writer had very good summer holidays because he learned to swim and did his work well.
对, in this way l spent my vacation happily. and i not only studied well but also became a good swimmer. now i am in good health and high spirits.
 5.the text mainly tells us how the writer spent his summer holidays.
对, 这篇短文确实告诉了我们作者是怎样度过他的暑假.