Although____Spanish， he attended the course.
C
「句意」虽然只懂一点西班牙语，但他还是参加了这个课程的学习。
「难点」know是静态动词，不能用于进行时;选knows从句中又缺少主语。knowledge作“知识”讲时是不可数名词，但作“了解”讲时，前面可加“a”，常用于词组haveraknowledgeof中，所以选C)。
_________,themostcontroversialcandidateintheelectioncampaign,hehasbeenstronglycriticizedforhiscrudecommentsaboutwomen.
_____ifIhadarrivedyesterdaywithoutlettingyouknowbeforehand.
Thecompositionscontainedsofewerrorsthattheteachergotthestudents_____oneanother’spapers.
Theopeningceremonyisagreatoccasion.Itisessential_____forthat.