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.
When it was feared that the serfs might go too far and gain their freedom from serfdom,the protestant leaders joined the princes $at\, crushing$ them.

Improve the highlighted part of the sentence given below.
You cannot forbid $him\, leaving.$

Improve the highlighted part of the sentence given below.
Realising the significance of technical education for a developing country,the government $laid\, aside$ a large sum on it during the last plan-period.

Improve the highlighted part of the sentence given below:
The reason $why\, he\, wrote\, the\, letter\, was\, because$ he could not contact him over the phone.

Improve the highlighted part of the sentence given below.
She says she's already paid me back, but $I$ can't remember, so $I$'ll have $to\, take\, her\, word$.