单选题 Because weekend sailors can not always the wind, many sailboats have auxiliary engines.
【正确答案】 C
【答案解析】这里需要区别upon与这四个动词搭配时所表达的不同意义。count upon/on意为“指望,依靠”;bear upon/on意为“与……有联系,关系到,影响”;hold upon/on意为“坚持(下去)”;come upon/on意为“碰上,找到”,意思接近come across.