I don't remember___________ to the airport that year.
One of the requirements for the experiment is that the material _____ to its burning temperature.
---- Occasions are rare _____ I can spend a day with my daughter. ---- You should spare some time to accompany her.
I will never understand how it ______ that you failed in the examination for you are such a good student.
----Do you have any idea why Mark is leaving?---- No. In fact, everyone is ________about it.
--- Have you heard that Jenny, along with her classmates, to Harbin for the winter vacation?--- Really? No wonder I haven’t seen her these days.