Question

一般现在时在周末只能用on weekends吗

Answer 1

on weekends 意思是在每周末，这个是陈述的一般情况，所以用一般现在时。
例:Usually I go shopping and play basketball on weekends.
最后两个要看具体用在什么情况下，有时用过去式，过去完成时，有时用将来时，但是on weekend 好像不常用，常用的是in the weekend,比如:
The teacher didn't blame him for what he did in the weekend/on Sunday.(过去式--What he did in the weekend.)
The teacher didn't blame what he had done in the weekend /on Sunday(过去将来时)
The techer won't blame him for what he will do in the weekend/on Sunday (将来时)

希望我的回答能够帮助你，!