A.We must immerse ourselves in hard work, we have difficult task to accomplish and bear a heavy responsibility on our shoulder. B.We must immerse ourselves in hard work; we feel a heavy burden on our shoulder and bear a heavy responsibility. C.We must immerse ourselves in hard work, we have difficult task on our shoulder and bear a heavy responsibility. D.We must immerse ourselves in hard work; we have difficult task to accomplish and a heavy responsibility to bear.