Tenses

[rajeshmalladi]

1) He looked as though he had run ten miles.
He looked as though he has run ten miles.

2) If I have the money I will buy a new car.
If I have the money I would buy a new car.

3) Last year I felt that I will/can do better this year.
Last year I felt that I would/could do better this year.

4) I have had dust allergy for the past one week.
I had dust allergy for the past one week.

5) I have been feeling sleepy all the time.
I feel sleepy all the time.

Please explain the difference among the above pairs of sentences atleast in brief.
Thanks so much.

[Rusty]

1) He looked as though he had run ten miles. (OK).
He looked as though he has run ten miles. (Incorrect).
He looks as though he has run ten miles. (Correct).

2) If I have the money I will buy a new car. (Correct).
If I have the money I would buy a new car. (Incorrect).
If I had the money I would buy a car. (Correct).

3) Last year I felt that I will/can do better this year. (Incorrect).
Last year I felt that I would/could do better this year. (Correct).

4) I have had dust allergy for the past <strike>one</strike> week. (OK).
I had dust allergy for the past one week. (Incorrect).
I had dust allergy for one week. (Correct).

5) I have been feeling sleepy all the time. (OK).
I feel sleepy all the time. (OK).