Please, in a situation of "asking the way" you would say:
"go past the bank", "past the bank", "go pass the bank", "pass the bank" - are all expressions correct?, is there any difference among them?
"Go past the bank" and "past the bank" are both correct and basically the same (here past is a preposition)
"Pass the bank" is unusual. It would probably be better to say "you'll pass the bank" (you will go past the bank).
"Go pass the bank" is not possible. (pass is a verb)
Also, I would like to ask you if I can use words "fruit" and "vegetables" both in singular and plural and vice versa and then what are their meanings?
The noun “fruit” can be either countable or uncountable, depending on context. It is usually uncountable when we speak of “fruit” in a non-specific way, for example in the sentence: “We must eat five servings of fruit and vegetables every day.”
Even when many different kinds are involved, we can still use “fruit” as an uncountable noun, for example when offering a guest a plate with slices of papaya, pineapple and melon, we say: “Have some fruit.”
When emphasising the different kinds of fruits, we usually use the countable noun, e.g. in the sentence: “I love Malaysian fruits, especially, guavas, mangosteens and papayas.”
When speaking of only one type of fruit, we can use “fruit” either as an uncountable or a countable noun. Below are some examples from a nursery website in the United Kingdom of how both “fruits” and “fruit” are used to refer to one type of fruit on one tree:
“Standard Lemon Tree. A vigorous plant to give a plentiful supply of juicy lemons. A lovely standard tree with fruits.”
“Your very own mango tree. What could be more exotic than that? Red and yellow fruits from June.”
“Avocado Tree. Dark-green, thick-skinned, pear-shaped fruit has buttery-textured flesh. Great for salads or home-grown Guacamole.”
The noun "vegetable" is almost always used as a countable noun: "Can you pass me the vegetables, please?" "vegetables are very good for you". However it is possible to use it as an uncountable noun (although I only discovered that today) when talking about vegetable as a substance: "You shouldn't have too much vegetable in your diet". Vegetable as an uncountable noun is extremely rare.
Thank you very much.