请问这个怎么填空！！

studs = [{'sid':'103', 'Chinese':90, 'Math':95, 'English':92},{'sid':'101', 'Chinese':80, 'Math':85, 'English':82},{'sid':'102', 'Chinese':70, 'Math':75, 'English':72}]
scores = {}
for stud in studs:
    sv = stud.items()          # (1)
    v = []
    for it in sv:
        if it[0] == 'sid':
            k = it[1]
        else:
            v.append(it[1])
    scores[k] = v                 # (2)
so = list(scores.items())                # (3)
so.sort(key=lambda x:x[0], reverse=False)
for l in so:
    print('{}:{}'.format(l[0],l[1]))

三个空都按上面填就好了

请你先说一下你的思考，先试着填一下吧。