We must be strict _____ ourselves _____ our work.

Jack, please tell Tom to call me when he ______ back.

More and more people come to visit Jingzhou Ancient City.—That’s true. It has become the of Jingzhou.

We breathed a sigh of relief hearing the news that the doctor _______him safe and sound.

How often do you drop your e-pal a line—_______, but usually once a week.