6. Jack doesn’t know all the answers, though he pretends to.
Jack acts as if he knew all the answers
7. The realization of what she had sacrificed for him led him to believe she was all the world to him.
Not until he realized what she had sacrificed for him did he believe that she was all the world to him
8. We rely too much on the Internet. Therefore, our lives are in danger of becoming more impersonal.
Were we not to rely so much on the Internet out life wouldn't be in danger of becoming more impersonal
9. Their work on developing an H1N1 vaccine is already under way to cope with the new strain.
They are under way to cope with the new strain because of their work on developing an H1N1 vaccine
10. Nowadays I consider taking up a hobby to be far less important than I used to.
Nowadays I don’t attach nearly to taking up a hobby as much as I used to