有英文句子既問題想問問

前一句應該用 future tense，例如

"we are going to hold an activity next Monday."

後一句如果是陳述事實用 present tense 並無問題。

（註：'activity' 前面應該用 'an'，你懂的。）

We are holding a activity next Monday. The activity is related to xxx.
Correction as follows: We are going to holding an activity which is
related to so and so next Monday.

No problems for tense, but we shall use "an activity".

For future tense, indeed we can use "we will hold", "we are going to hold" or "we are holding". Thus, you got it right in terms of tense.

We can find out that the simple future expresses possible or probable activity in the future.
Hence:-We will hold an activity ,(probably related to xxx), next Monday.
We shall have/carry on/celebrate/hold/keep/keep back/go/support/ are the simple future tense.
The tense has no problem.

如果呢個 activity 係到而家重一直安排緊, 到下星期一開始, 咁用現在式係可以既, 否則, 用將來式會好的.

We will hold a activity related to XXX next Monday.