—What are you busy ___?—I’m busy ___ a letter to my mother.
Nancy enjoyed herself so much ______ she visited her friends in Sydney last year.
It looks like the weather is changing for ______ . Shall we stick to our plan?
______ you eat the correct foods ______ be able to kiip fit and stay healthy.
By the time he realizes he ______ into a trap, it’ll be too late for him to do anything about it.
------Is there anything wrong , Bob? You look sad. ------ Oh, nothing much. In fact, I ______ of my friends back home.