If you insert a j at the beginning of the set and then insert a word space and another j within the set, you will get a two-word phrase that is an English expression: jumbo jet

Figure out the letter that, used twice (once after a word space), will make a two-word English expression out of each of the following sets of letters.

1. erriblewos
2. tudykills
3. astood
4. oubleate
5. ogays

1. terrible twos
2. study skills
3. fast food
4. double date
5. dog days