七年级学生可以用以下简单的英语句子来介绍春节：

1. Spring Festival is the most important traditional festival in China.春节是中国最重要的传统节日。

2. It usually falls between late January and mid-February, depending on the lunar calendar.春节通常在农历腊月至正月之间举行。

3. The festival lasts for 15 days, starting from the first day of the lunar new year.春节持续15天，从农历新年的第一天开始。

4. People celebrate Spring Festival by cleaning their homes, wearing new clothes, and decorating their homes with red lanterns and couplets.人们通过打扫房屋、穿新衣服和挂红灯笼对联来庆祝春节。

5. Fireworks and dragon and lion dances are also common during the festival.春节期间，放鞭炮、舞龙舞狮也很常见。

6. Families gather together to have a big feast on New Year's Eve and exchange red envelopes filled with money.除夕夜，家人团聚共进年夜饭，互赠红包。

7. Children usually receive new year's gifts and blessings from their elders.孩子们通常会从长辈那里收到新年礼物和祝福。

8. Spring Festival is also a time for people to wish for good luck, prosperity, and happiness in the coming year.春节也是人们祈求来年好运、繁荣和幸福的时刻。

9. Besides celebrating the festival, people also visit temples to pray for good fortune and pay respect to ancestors.除了庆祝节日，人们还会去寺庙祈祷好运，并向祖先祭拜。

10. Spring Festival is a time of joy, reunion, and cultural heritage for Chinese people.春节是中国人欢乐、团聚和文化传承的时刻。