Add one of the following word to make each pair simple sentences into a compound or complex sentences
(But,therefore,and,which,become)
1-my new assistant can type very well. he hasn't much experience with computer
2-I found useful acting website. I shared it with my friends
3-I left my bag on the bus.i didn't have a pencil
4-this is a great opportunity.i should not be lost
5-this soup was to cold.i warmed it the microwave