He ______ be at home, because the light in his room is on.

He had a stomachache ________ he ate something bad this morning.

I won’t call you, ______ something unexpected haappens.

–Mr Green,      can we do to protect ourselves when facing dangerous attackers in public places?–Always remember “run, hide and fight” when you are in danger.

David doesn’t give up _______ he has failed in the experiment four times.