前半句不懂, children spend too much time on watching TV on vacation.
这里用的是一般现在时。你的题有可能是一般过去时把spend换成spent就行了
What concerns us most is that the children spend too much time watching TV during the holidays.
What worries me is that kids spend too much time on TV on vacation.
what worries people is that children spend too much time watching TV in holidays.