小题1:A
小题2:D
小题3:A
小题4:C
文章是介绍了the camper trailer的具体情况。
小题1:推理题。根据第三段So many camper trailers have been designed for people to live in the trailer long term以及最后一段Camper trailers can also be rented and used for a shorter period of time。可知trailers适合于长短途旅行。
小题2:猜测词义题。根据句意可知这里意为：供选择的。可以代替帐篷的。
小题3:主旨大意题。通读全文可知文章是介绍了the camper trailer的具体情况。
小题4:细节题。根据第二段第二行The smaller trailers usually have just enough room for two people to sleep and store a few personal travel items.