一群人微笑是个多么诡异的场面啊...... 但是雅思考官就偏偏让大家描述这样的场景。于是我们就尽量挑一个不那么诡异的场面说吧...
　　那在雅思考试中一群人能够自然的笑，第一个能想到的，除了饭店的服务生，就只有大合照了：
　　This topic reminds me of the time we took class pictures on graduation day.
　　Actually, we all had mixed feelings, on the one hand, we were pretty psyched about graduating from university and getting a diploma, on the other hand, we also felt a little bit sad 'cause we had to say goodbye to all the classmates who have spent the last four years with each other.
　　However, when we took the picture, we still didn't forget to be funny. I mean, we made faces and posed hilariously to the camera despite the photographer's objection. He was so pissed off. In the end, he couldn't stand us anymore, and shouted, couldn't you guys act like normal people and just smile to the camera?
　　After we were done having fun, we thought, maybe we should listen to the photographer and take a decent picture together. So we stood still, and said cheese when he clicked the shutter.
　　After we got the picture, we were surprised to see that everybody looked great in the picture, I mean, we all had a sweet smile on our face, looking energetic and hopeful.
　　I framed the picture and put it on my bookshelf. It would bring back memories from my college years. Every time I saw those smiling faces I would recall all the precious moments we had together during those four years, and I just couldn't help cracking a smile.
　　语言解析：
　　mixed feelings = mixed attitude or opinion about something 例如：
　　She had mixed feelings about giving up her job.
　　on the one hand... on the other (hand)... = used to introduce different points of view, ideas, etc, especially when they are opposites 例如：
　　On the one hand they'd love to have kids, but on the other, they don't want to give up their freedom.
　　psyched = excited, especially about something that is going to happen 例如：
　　The kids are really psyched about the vacation.
　　pull/make faces/ a face (at somebody) = to produce an expression on your face to show that you do not like somebody/ something or in order to make somebody laugh 例如：
　　What are you pulling a face at now?
　　Do you think it's funny to make faces behind my back?
　　piss somebody off = to make somebody annoyed or bored 例如：
　　Her attitude really pisses me off.
　　shutter = the part of a camera that opens to allow light to pass through the lens when you take a photograph 例如：
　　the quiet click of the shutter
　　bring something back = to make somebody remember something or think about it again 例如：
　　The photographs brought back many pleasant memories.
　　The incident brought back childhood insecurities.
　　can not help (doing) something| can not help but do something = used to say that it is impossible to prevent or avoid something 例如：
　　I can't help thinking he knows more than he has told us.
　　She couldn't help but wonder what he was thinking.