Basically, conditional sentences are used to talk about:

1/ A situation which sometimes exists or existed:

If they lose weight during an illness, they soon regain it afterwards.

If he saw me in the street, he’d just say ‘Good morning.’

2/ A situation which you know it does not exist:

If England had a hot climate, the attitude would be different.

3/ A situation which you don’t know whether it exists or not:

If he is right, it would be possible once more to manage the economy in the old way.

4/ A situation which may exist in the future:

If I marry her, we shall need the money to live on.

Unless: means ‘If…not’. Eg: You will fail your exam unless you work harder (If you don’t work harder).

When we want to quote somebody’s words or thoughts, we can do it in two ways:

1. DIRECTED SPEECH:

Eg:

So he comes into the pub and says “I’ll have a pint”.

And then I thought “Well, does he really mean it?”

“Your information,” I replied, “is out of date.”

“I suppose so,” grunted Jack.

2. INDIRECTED SPEECH:

Eg:

So he comes into the pub and says (that) he’ll have a pint.

And then I wondered whether he really meant it.

***Tenses and Aspects:

The difference between tenses and aspects is that the tense is used to express the relation between the happening of an action and the time at which the action happens.

• In the English language, there are three tenses: the present tense, the past tense and the future tense.

Eg: He is now in Hanoi with me. Last week, he was in Thailand. Next week, we will be in Hong Kong.

• But the aspect is used to denote different characteristics of an action. In the English language, there are three aspects: The indefinite aspect, the continuous (progressive) aspect and the perfect aspect. These aspects have different functions as follows:

1/ The indefinite aspect: it has two main functions:

a)  It denotes a habit or a repeated action:

He never gets up early. Last year, he always came to see me on Saturday evenings. Next week, he will be in Hong Kong.

b)  It denotes a permanent property of an action:

She is terribly beautiful. Years ago, he was very good to me.

I. DEFINITION & CATEGORIES:

Verbs: are semantically words that designate actions (kiss, run), process (grow, change), experiences (know), or states of being (be, have)…

Finite Verbs: are verbs in the present or past tense. A finite verb must normally have a subject (which may be hidden) and a tense (a finite verb can also be called a tensed verb).

Eg: She knows me. We knew that.

Non-finite Verbs: are verb forms without a tense (a non-finite verb can also be called non-tense verb or tenseless verb). They include infinitives (present or perfect, with or without ‘to’), present participles, past participles, and gerunds, etc.

Eg: the non-finites of verb ‘do’ are to do, do, to have done, have done, doing