秦国发展成为战国后期最富强的封建国家，主要是因为（   ）       

阅读下面短文，根据所读内容在表格中的空白处填入恰当的单词。注意：每个空格只填一个单词。

       Put a group of strangers in a room together, and they'll probably start a conversation. "Hot today, isn't it?"one might say. "You said it." another replies.

       Why do we talk so much about the weather? When we meet new people, we don't begin by telling them our life story. We start with small talk, a polite conversation about something like traffic or weather.

       Research suggests that small talk can build new friendships. When we begin conversations with new people, we want to feel comfortable, and so do they. We use small talk to find common interests. Once we have a common interest, a friendship can begin.

Small talk even helps people get hired. In order to impress at a job interview, you need to bond with the interviewer right away. Proper small talk can make that first impression get you the job.

        So, how can you make small talk lead to a new friendship or job? First off, find common ground. Select something around you that you share with the other person.

        Next, keep the conversation going. Compliment (赞美) the other person to make himor her feel comfortable, and ask questions to show interest.

        Third, keep eye contact (接触). When you look people in the eye, they feel you appreciate what they are saying. It makes you appear honest and builds trust.

         Naturally, shy people might not have enough confidence to start up conversations with strangers. Talking to someone you don't know is not the easiest thing to do! Some experts say with more practice, small talk does get easier.

         Some people avoid small talk because they dislike discussing things like traffic or weather. For them, they are just too small. However, when you think about it, small talk is anything but small. In fact, it is actually a very big deal!

读我国华南某城市2012年PM2.5月变化统计图，完成下列各题。