To the contractor, what is the significance of the difference ...

[maychende]

To the contractor, what is the significance of the difference between an avoidable delay and an unavoidable delay?
 
  What will be an ideal response?

Question 2

What defines the start date and what defines the finish date of a contract, with the bracketed time being the project duration?
 
  What will be an ideal response?

[joshraies]

Answer to Question 1

An unavoidable delay is one for which the contractor can have some confidence
of receiving a time extension and possibly monetary compensation. The contract
documents will generally provide some guidance as to the appropriate procedures that are
to be followed to permit some relief for the contractor when unavoidable delays occur.
An avoidable delay,. on the other hand, implies that the contractor was or should have
been in control of circumstances and could have taken appropriate actions so the delay in
question would never have occurred. The contractor should have no expectation of
receiving a time extension or any damages for avoidable delays.

Answer to Question 2

The start date is generally specifically noted in the Notice to Proceed. The start
date may be specifically given or it may be stated in terms of the date of the Notice to
Proceed, e. g., ten days from the date of receipt of the notice to proceed. In some
contracts, the start date is the day the notice to proceed is received by the contractor.

The finish date of a contract (defining when no liquidated damages will be assessed
against the contractor) generally occurs at the point of substantial completion. Substantial
completion is the point in a project at which the owner is able to occupy the facility being
constructed and use it for its intended purpose. Only minor items of work may remain at
the time of substantial completion. These deficiencies are commonly itemized in the
punch list.

[maychende]

Gracias!

[blakcmamba]

Great answer, keep it coming