一些Tense既問題

1. It is very warm in this room. I will switch on the air-conditioner.
點解個答覆係will switch.......點解唔可以用will be switching

Will be switching is a future continuous tense.

Future continuous tense is used to :

a. talk about a action that lasts for a period of time in the future
example : I will be watching TV tonight after my dinner.

b. talk about 2 actions, 1 is a future continuous tense that lasts for a period, another 1 is a short term action that is going to happen in that period.
Example : I will be watching TV when Mary visits me tonight.

c. talk about 2 actions happen together in the same period. Again these will be a longer action.
Example : Tonight I will be cooking dinner and John will be washing clothes.

Your sentence 1 is only a short action “switch on” and also it is happening “now”, not in the future. Therefore you cannot use “will be switching”.

2.Elaine can give the note to Jim's form teacher. She will be seeing her tomorrow. – This is an example of definition (a).

點解個答覆係will be seeing.........點解唔可以用will have seen :
“Will have seen” is a Future Perfect Tense :

a. to talk about an action that will happen after another action. Both actions will happen in the future.
Example : When you arrive home tonight, I will have finished my homework.

b. to talk about an action that will happen before a specific time in the future.

3.By the end of next year, the prices of most consumer goods will have gone up.點解個答覆係will have gone up .......點解唔可以用will be go up - For this sentence we have to use Future Perfect Tense. Please look at definition (b). By the end of next year = before the end of next year.