问题补充：
Come and join us. We are short of hands.
A. We need help.
B. We hurt our hands.
C. Our hands are short.
D. We can do it by ourselves,
答案：
(答案→)A. We need help.
B. We hurt our hands.
C. Our hands are short.
D. We can do it by ourselves,
解析：We need help.我们需要帮助；We hurt our hands.我们弄伤了手指；Our hands are short.我们的手很短；We can do it by ourselves,我们可以自己做。句意：来加入我们吧。我们很缺少人手。结合语境可知此处指的是，需要帮忙。故选A。
