MR. GOLDSMITH ____ IN HIS OFFICE WHEN SOMEBODY THREW A STONE THROU...

70. - DE THI THU DAI HOC MON ANH VA DAP AN
DE THI THU DAI HOC MON ANH VA DAP AN
70. Mr. Goldsmith ____ in his office when somebody threw a stone through the window.a. worked b. is working c. has worked d. was working