Because the shop all the T-shirts are sold at half price.A. has closed downB. closed down

问题补充：

Because the shop, all the T-shirts are sold at half price.

A. has closed down

B. closed down

C. is closing down

D. had closed down

答案：

A. has closed down

B. closed down

(答案→)C. is closing down

D. had closed down

解析：考查时态。根据后半句：T恤半价出售，说明这家店还没有关门，只是即将关门。故C正确，现在进行时表示将来时。