Jim and his brother are doing()homework now.A they B their C them 告我原因好吗?

Jim and his brother are doing()homework now.A they B their C them 告我原因好吗?
Jim and his brother are doing()homework now.
A they B their C them 告我原因好吗?

Jim and his brother are doing()homework now.A they B their C them 告我原因好吗?
B
they是名词,做主语：他们
their是they的形容词结构,做谓语：他们的
them是they的宾格,做宾语

their他们的
they他们
them他们（宾格）
你说用哪个呢？
做他们的功课啊，不是他们功课

选B 表示他们的 A是他们 C是他们 用作宾格