Question

4.His sister is office worker. She works in office over there.

A.an;an   B. the;the

C.an;the   D. the; an

Answer 1

4.C    an office worker意为“ 一位办公室职员”，office以兀音音 素开头，因此用不定冠词an;the office over there意为“那儿的 那间办公室”，表特指用定冠词the。