문법이요

p70  28. We _______  your e-mail about problems with the

heating system in the downtown office.

a) are receiving   b) receive   c) have received   d) receiving

에서 a)와 c)번 둘중에 c)가 정답인 이유는요? 해석에 따라 답이 정해졌나요??

p71  35. The item( you are requesting a refund for

needs to) _______ on your return form.

a) indicating   b) indicate   c) have indicated   d) be indicated

에서 ( )괄호안에 needs to의 to 목적어가 the item 인거죠?? 그래서 the item의

동사 자리인거구요 ? 첨에 동사가없어서 놀랬어요

p77  15. The new presentation system ________ by the

convention center's audio visual team.

a) had installed   b) will install   c) was installed   d) is installing

a)와 c) 둘중에 c)가정답인 이유는 해석인거죠?