________ he has many friends, he is often feeling lonely.
C
状语从句的从属连词的选取。
InEurope_______arethetwoleadingcontendersforaglobalreservationssystem.
Touristexpenditureshavedifferenteffectsonadestinationeconomy:salesbyfoodvendorstorestaurantsare_______effect;whiletaxifaresandairlineticketsalesare_______effect.
WhichofthefolloingisNOTincludedinthefabledFiveMountainsinChina?