Sentence Structures

1. Simple Sentence
a. I was writing to complain about the unsuccessful installation.
I am writing to complain about the unsuccessful installation.
b. I am going to watch a flim.
I was going to watch a flim.
c.I am writing to talk about the clothes.
I was writing to talk about the clothes.
d.I don't understand what you are talking about.
I didn't understand what you are talking about.
e.Do you know what you are doing?
Did you know what you are doing?

2. Compound Sentence
a. The PaL system is the territory-wide standard in Hong Kong and the system is widely used in Asia.
The PaL system was the territory-wide standard in Hong Kong and the system was widely used in Asia.
b.Insurance cannot cover everything, but it does cover the big expenses accrued while giving birth.
Insurance could not cover everything, but it did cover the big expenses accrued while giving birth.
c.Emily listens to the music and Billy watches the movie.
Emily listened to the music and Billy watched the movie.
d.Vicky wants to go shopping but Mark doesn't want to.
Vicky wanted to go shopping but Mark didn't want to.
e.I don't like writing and Vicky doesn't like running.
I didn't like writing and Vicky didn't like running.

3. Complex Sentence
a.I cannot understand why you agree to the installation.
I could not understand why you agreed to the installation.
b.The phrases in the following sentences add information to the base sentence but cannot stand alone.
The phrases in the following sentences added information to the base sentence but could not stand alone.
c.I know why Billy wants to listen to this song.
I knew why Billy want to listened to this song.
d.If you learn how to play this games, you will love it.
If you learned how to played this games, you would love it.
e.The kids need to go to bed after they finish their homework.
The kids needed to go to bed after they finished their homework.