Люди кто шарит в англ грамматике,пмогите плз с tenses,у мя тут ппц голову сломал,если кто возьмётся плз чуток объяснения

1) It is already 8 o’clock. By the time I ARRIVED in the classroom, the teacher HAD already EXPLAINED the Subjunctive mood and my classmates WERE WRITING sentences to prove their understanding.
2) On the following Saturday I SHALL CELEBRATE my birthday. I HAVE already INVITED a lot of guests. By the time they WILL COME my mother, my sister and I SHALL HAVE already LAID the table. I told my friends that I WOULD WAIT for them at the station, but now I AM afraid I WON'T BE ABLE to finish everything by that time.
3) By the time mother CAME, I HAD already DONE my lessons and WAS READING a book.
4) What you WOULD SAY if I ASK you to help me with my homework ?
5) She just imagines that when she ENTER her mother WILL BE COOKING supper, her father WILL HAVE already WATCHED his favourite program, and WILL BE READING a newspaper, while her brother WILL BE PLAYING with his toys.
6) Why DIDN'T you ANSWER? she cried. Because you TOLD nonsense.
7) I surely HAVE SLEPT very long, said Florence. When DID I COME here? Yesterday?
8) Our train STARTS at 8.30 tomorrow, so if you COME at 5 o’clock we SHALL BE still PACKING.
9) He says he HAS BEEN LISTENING to the same tunes for fifteen years.
10) The Bartons HAVEN'T HAD dinner by the time Alice calls on them.

Чуть-чуть поправлю postie.
2) On the following Saturday I AM CELEBRATING my birthday (планы на ближ. будущее)... By the time they COME... (придаточное времени)
4) What WOULD you SAY...(вопрс)
5)....when she ENTERS...
6) Здесь возможны варианты.. . Why aren't you answering?...Because you ARE TALKING nonsense
7) I surely SLEPT very long ...( нет связи с настоящим)

was