MUM IS ALWAYS BUSY _____ HER WORK IN THE LABORATORY.A. WITH B. AT...

15. Mum is always busy _____ her work in the laboratory.

A. with

B. at

C. in

D. of

16 Lan will stay there _____ the beginning in September _____ November.

A. from/ to

B. till/ to

C. from/ in

D. till/ of