One of the most important questions they had to consider was__________ of public health
—Where’s that report?—I brought it to you __________ you were in Mr. Black’s office yesterday.
The field research will take Joan and Paul about five months; it will be a long time __________ we meet them again.
It has been announced that candidates(应考者) ________ remain in their seats until all the papers have been collected.
I ________ pay Tracy a visit, but I am not sure whether I will have time this Sunday.
The book was written in 1946, __________ the education system has witnessed great charges.