The rocket will travel to Mars _________ a speed of over 25,000 miles per hour.

－Gina， do you like playing_______guitar－Yes， I do.

I should apologize to you for failing to visit you last week, but I’ve been very busy_____ the past few months

The music sounds_________. It __________ running water.

It is often recommended that children________chances to get close to nature.[ ]