Selecting a mobile phone for personal use is no easy task because technology ____ so rapidly.

---- Look! Everything here is under construction. ---- What’s the pretty small house that ____________ for?

 —What happened to Tom?—He ______ his leg while playing football with his classmates.

—May I speak to your manager Mr. Williams at five o’clock tonight?—I’m sorry. He ________ gone to a party long before then.

The train ＿＿＿＿＿ at the present speed until it reaches the foot of the mountain at about nine o’clock tonight.