Improve the highlighted part of the sentence given below: Mr. Smith arrived $at$ India in June last year.

Improve the highlighted part of the sentence given below:
He should move on to the next point,and not $harp\, one\, sting\, only.$

Improve the highlighted part of the sentence given below.
Why the dinosaurs died out $is\, not\, known.$

Improve the highlighted part of the sentence given below.
The poor villagers $have\, waited$ in the bitter cold for more than $4$ hours now.

Improve the highlighted part of the sentence given below.
$His\, powerful\, desire$ brought about his downfall.

Improve the highlighted part of the sentence given below.
To get one's name in the Rowland Ward's book of hunting records was the $hot$ ambition of every serious hunter.