It worried her a bit ____ her hair was turning grey.
The most challenging job for game designers is to make their games interesting__.
--- I don't remember having ever seen John since last week. Has he gone somewhere?一Not really. He__his newly-bought apartment.
.After many trials and failures, the farmer__built a homemade plane that successfully got off the ground.
--- Jane is lucky to have got the well-paid job.一Yes, __she is inexperienced and young.
The writer revealed that the story was__by real life events, though the characters were fictional.