I will call you when I get home.
She cried because she was upset.
Although he was exhausted, he stayed up to finish his homework.
She is so busy that she can’t call you.
when, whenever, as, while, as soon as, before, after, since , till, until，by the time, every time, the minute, the moment, the instant, immediately , directly, no sooner … than, hardly …when, hardly…before
because, since, as, for, seeing that
so that, in order that, lest, in case
so … that, so that, such … that, such that
though, although, even if, even though, while;
no matter what/who/where/when/how/which;
whatever, whoever, wherever, whenever, however, whichever;
as, than, as…as…, no more than, not more than
as, as if, how, the way
if, unless, as long as/so long as, providing (that), provided (that), on condition that, only if