I can never forget the days _____ we worked together and the days _____ we spent together.A. when; which B. which; when C. what; that D when; when
______ in London, the penniless American wandered on the pavement, ______ to find a job to make a living.
Once ____________ , a plan should be carried out.
Being a parent is not always easy, and being a parent of a child with special needs often carries with _______ extra stress.
Between the two periods of classes is a break, _______ we can have a short rest.
Jumping out of ________ airplane at ten thousand feet is quite ________ exciting experience.