—Whose model plane is it? —It’s Jack’s. He made it by . A. he B. himself C. his

问题补充：

—Whose model plane is it? —It’s Jack’s. He made it by .

A. he B. himself C. his

答案：

解析：句意：这是谁的飞机模型？——是Jack自己做的。by oneself靠某人自己，故选B.