1.It was due to the fact (which改that) he had been working very hard that he got a promotion.
2.I just don't understand( why 改what)it is that prevents so many teenagers form being as happy as expected.
1.It was due to the fact (which改that) he had been working very hard that he got a promotion.
2.I just don't understand( why 改what)it is that prevents so many teenagers form being as happy as expected.