The plane is flying ____ a speed of 500 kilometers an hour ____ the way to Kunming.
Some researchers believe that there is no doubt ________ a cure for AIDS will be found.
Mum is coming. What present _______ for your birthday?
Danny left word with my secretary _______ he would call again in the afternoon.
Elephants have their own way to tell the shape of an object and _______ it is rough or smooth.
—Why does she always ask you for help? —There is no one else _______, is there?