now for the non durative verbs:
attention, we cant say verb + 一 + verb or verb + verb
for example we cant say 来一来(come) 到一到(come) 死一死(die)
but we can say verb + 一下
this is because we want to highlight the action will finish in a very very short while.
for example, when you need your friend's help, you can call him like this 我需要帮助,你能来一下吗? (I need some help, can you come here for a little while?) so you want to highlight I just need a few help, your friend dont need to stay here for a long while to help you.
of course, for the non durative verbs, we can also use simply them alone, it means just verb, no 一下
the same example: 我需要帮助,你能来吗? 来---come is a non durative verb so ofc we can use it alone. if you add 一下, you just want to highlight the action will finish in a very short while.
but, for durative verbs, we cant always use it alone. for example,
我们出去走(一)走吧。 let's go out for a walk. if you say 我们出去走。 chinese can understand this but it is really really weird. we never say it like this.
the rule is: normally, we cant use the durative alone, except for a hope, for a wish , for an order , for a request etc, anyway for something about emotions.
for example, 我想看电视。 I want to watch TV. "want" is a kind of hope.
我想尝你做的饭。 I want to taste your cooking.
look at the example at the beginning: 我可以尝(一)尝/尝一下你的饭吗? this is a request so we can also say 我可以尝你的饭吗?
so the rule:
for the durative verbs, we usually use them as verb + 一 + verb or verb + verb or verb + 一下
normally these are the same, except you want to highlight something different according to the duration of the verb. AND for the emotions, we can use the durative verbs alone, however, we can also use them as verb + 一 + verb or verb + verb or verb + 一下 in the cases about emotion
for the non durative verbs, we can just use them as verb alone or verb + 一下 its the same
a little hard ~~~~ practise more~~