Her parents’ quarrelling with each other _________ is the main cause of her family’s breaking up.

what do you think of the job of being a nurse—In my opinion, it ____ be difficult sometimes though it seems easy.

Trust him please! When he _______ reading it, he will return the book to you on time

When you talk about a person’s _____, you are referring to the country, race, or social class of their parents or ancestors.

Can I ______your dictionary? –Sony, I’m using it.