以下关于目标的说法，正确的有（  ）
①没有行动，一切目标都将落空              ②只要有目标，行动有无无所谓
③目标应该是相对稳定的                          ④目标应该有长期和短期之分

如图为生态系统中能量流动部分示意图（字母表示能量），下列正确的是（　　）

根据短文内容，选择最佳答案。

Schedule a Tour

    University of South Carolina （USC) is famous for its warm southern hospitality（好客）. Schedule a visit and feel it in person. Our walking tours are led by current students, called University Ambassadors, who are looking forward to telling you what it's like to live and study in USC. Our walking tours run Monday through Friday and most are around 2 hours. The university will be closed on Tuesday, July 4, 2017 in observance of the holiday. We welcome your visit year round and will be ready for you, rain or shine. Please refer to the list below to determine which tour is best for you and remember to book at least two weeks in advance.

如果你有5000元预算，你是买一块瑞士产的机械手表，还是买一块智能手表？很多人会选择瑞士手表，因为他们觉得瑞士手表是质量和品味的代名词，更是时尚和声望的象征。昂贵的价格，使得瑞士法郎（约合人民币1375亿元）。从文化生活角度看，这给我们的启示是（    ）