我需要列出一个循环中临时变量中存储的多个值

您可以使用 itertools.chain :

from itertools import chain

marks={"Farah":[20,40,50,33],"Ali":[45,38,24,50],"Sarah":[50,43,44,39]}

output = list(chain(*marks.values()))
print(output) # [20, 40, 50, 33, 45, 38, 24, 50, 50, 43, 44, 39]

for

output = []
for val_list in marks.values():
    for v in val_list:
        print(v)
        output.append(v)

print(output)