Here are some suggestions to complete the sentences based on the provided context:

1a) At university, Catharine was a **dedicated** student. Needless to say, she passed all her exams with flying colors.
1b) This new... of the car can easily reach 100 kph in just under six seconds.
1c) I hate it when she tries to... herself on Britney Spears. She looks and sounds so unnatural.

2a) The country has the largest number of national parks and... reserves in the world and is an example for others to follow.
2b) Jennifer gave the... away when she began giggling behind his back. This made him suspicious.
2c) They were both sitting in the armchairs hunching over the desk and playing a... of chess.

Let me know if you need help with anything else!