Some researchers believe that there is no doubt ______a cure for AIDS will be found.

________ TV drama You Who Came From the Stars tells a love story between a 400-year-old alien and ________ attractive human girl.

“Be careful, do not stand ___________ to the fire, Jim.” Mrs. Thompson said to her little son.

She asked us _____ the dialogue and try to recite it.

I’d like to trek ________ the jungle.[ ]