check grammer

WHEN will you leave in Monday?
(WHAT TIME變成WHEN..唔洗要個BE..因為leave已經係動詞)

Could you going to the another place, such as Mongkok?

she is still not confirm the actual time for me.

Can I let you know once available?

(冇問題)

yhgemma's answer is better
Or yaumatei2000 's.

There are a few errors in this answer (only the first and last lines are completely correct)

你星期一要幾點走?
What time are you leaving ON monday
OR
-When will you be leaving on monday.

After - BE must be ING, not be leave, be leaving
Could you GO to another place such as Mongkok?
但是她仍未給我確實的約會時間
-but she's still uncomfirmed with the meeting time.
我會遲後再跟你確實約會時間
I will comfirm with you later.

What time will you be leave in Monday?

When / What time will you leave next Monday? or
When / What time are you leaving next Monday?
You can either use "on" or "next". As you are talking about the future, it sounds better to use "next". But it is definitely wrong to use "in". For days of the week, we need to use 'on'.


Could you going to the another place, such as Mongkok?

Will you be going to other places, such as Mongkok?
1. 'Could' is a modal auxiliary verb (助動詞), it takes a bare infinitive. So after could, you should use 'go' instead of 'going'.
Also, 'could' is used:
- to show abilitity, e.g. i could swim (the past tense of 'can')
- to request, e.g. could you do me a favour?
therefore it's wrong to use 'could' to ask the question here.
2. 'going' is present participle, you need to put a 'verb to-be' infront of it
3. you don't know how many places there are, therefore you should use 'places'.


She is still not confirming the actual time for me.

She has not yet confirmed the actual time with me.
You need to use the present perfect tense because it is something that has not finished.
'For' should be replaced by 'with' because 'for' means 她替我確實時間 (she makes the decision)， while 'with' me means 她跟我確實時間 (we discuss the time together)

Can I let you know once available.
I'll let you know the time when it is confirmed.
'can I ....' (inversion) should be used for asking question, not in a statement.

When will you leave on Monday? 你星期一要幾點走?

I will contact your for details afterwards as she didn't give me the exact time of dating.但是她仍未給我確實的約會時間﹐我會遲後再跟你確實約會時間

What time will you leave on Monday? Could you go to another place such as Mongkok?

She still hasn't confirmed the actual time for me. Can I let you know once available?

At what time will you be leaving on Monday? Will you go to another place such as Mongkok?
She still hasn't confirmed the actual time with me. Can I let you know the time once it's confirmed.

What time will you be leave in Monday? Could you going to the another place, such as Mongkok?
She is still not confirming the actual time for me. Can I let you know once available.