The Noodle House has really good noodles. They are cheap, and they are great! You can get small, medium, or large bowls of noodles.

    The Noodle House has some specials. Special 1 has beef and tomato and is only ￥5. Special 2 has mutton and cabbage. It is ￥6. And Special 3 has chicken and carrot. It's only ￥8. I like it best.

    You can get some other great food at the Noodle House. For example, you can get 16 dumplings for ￥11. You can get great desserts! You can get strawberry, banana and orange ice cream.

    They are all nice! Try the Noodle House soon!

【旅游地理】阅读材料，回答问题。

克罗地亚于1991年独立，其独特的旅游资源吸引了越来越多的游客前来游玩。近几年，叙利亚内战催生了世界上最大的难民危机，2015年9月首批277名难民涌入克罗地亚。下图为克罗地亚的地理位置。

说明克罗地亚旅游资源的独特性及当前旅游开发中应注意的问题。

设$\left\{a_n\right\}$为等差数列，公差d = -2，$S_n$为其前n项和.若$S_{10}=S_{11}$，则$a_1$=（  ）