6.
Although India is still by far a poor country, it can become rich if its natural and human resources are fully utilised.

7.
The reason why he wrote the letter was because he could not contact him over the phone.

8.
As he is past his teens now, he can look for himself.

9.
There is no more room for you in this compartment.

10.
Most donors would seriously protest any effort to extrapolate from such limited data.