—Must I turn off the gas after cooking ? —Of course . You can never be _______ careful withthat.

－If I’m not mistaken, your birthday is coming up. Has your brother sent you anything?－Not yet. He never forgets, _________.

To children, good habits do not come        , so parents and teachers need to be their role models.

Apple’s iPad2 uses a 9.7-inch touch screen like the iPad. ______, it is equipped with a pair of new cameras, which the iPad doesn’t have.

Circus tigers, although they have been tamed, can _____ attack their trainer.