In fact, a small car is big enough for a family of three, you need more space for luggage.
A. once
B. because
C. as if
D. unless
网友回答
A. once
B. because
C. as if
(答案→)D. unless
解析：句意:事实上，如果你不需要太多的空间装行李的话，这辆小汽车对于这三口之家已经足够了。once一旦； because因为； as if好像； unless除非，如果不。根据句意故选D。