Are the prepositions needed?

I faced a trouble while writing a text, the trouble is: Do I have to used the prepositions in the end of the sentences below and do they look natural and well?

- Nicely done! You've made all your homework even though I hadn't told you to!

- While speaking fluently, people use as many contractions as they are able to (Probably "can" would have fitted better in here, but I wanted to check if "be able to" would look okay as well)

- The government has applied all the measures it was capable of

Thanks in advance!