Relative pronouns and adverbs

I'm not sure ___ pen this is.

I'm looking for the person ___ sent me the email.

The man ___ broke into our house was caught in two days.

New Year is the time of year ____ there are many parties.

The girl ___ brother goes with me to the gym is a good singer.

1960 was the year ___ my father visited the USA.

I don't understand the reason ____ you didn't do your homework.

London is the city ___ I first studied English.

That is the shop ____ was awarded as the best shop in the city.

This school is only for children ___ first language is not English.