1-I was going to phone you yesterday but i forgot
1)generative context
I had to finish all my assignmet yesterday cause i was on vacation all week i didnt got any help from my friends they were all busy by theyre own struggles.
The structure was going to is normally used to indicate future in the past,future inthe past is used to express the idea that in the past you thought something would happen in the future ,it does not matter if you are correct or not.
subject+past continuous/progressive for a past intention that was not realised
5)concept cheking questions .....
Did i phone you?       No
Was i carelless?         yes
Did i do anything wrong ?       maybe
Am i talking about future in the past ?         yes

2-she must have gone home by now.
1)generative context
Her daughter was calling her repeatedlly she was anxious about something so it made her nervios too.
2)we use must have to express that we feel sure that we feel sure that something was true in the past
modal verb + have +past participle
5)concept cheking .......
has she gone home yet ?     yes
was she serious about going home ?       yes
was it a good idea ?         maybe
am i talking about a sure thing that happen in the past ?       yes  

3-Open the window , will you?
I wonder if youd mind opening the window
1)It feels so hot and humid in the class it would be great if the window was open so the air would change a little bit but i cant reach the window with all these chairs in between.
we can use if or whether to report indirect yer or no questions and questions with if is more common than whether to express an alternative we can use or not with if and whether with if we use or not in end position only.
5)Did i open the window ?       maybe
was it necessary to open the window?       yes
am i talking about present or future?     present

4-shes phoned 3 times today
she phoned 3 times today