New Words：
sum [sʌm] n. 和，总和，总数；全部，一切
angle [ˈæŋɡl] n. 角；角度
Sample Sentences：
The sum of 7 and 12 is 19.
She paid the sum of $200 for dresses.
Please take pictures from a different angle.
An angle of 90 degrees is called a right angle.
New Words：
triangle [ˈtraɪæŋɡl] n. 三角形;三角形物体
Sample Sentences：
Cut the sandwiches into triangles.
The angles of a triangle total 180.
The sum of all the angles of a triangle is 180 degrees.
sum [sʌm] n. 和，总和，总数;全部，一切
angle [ˈæŋɡl] n. 角;斜角
New Words：
lunar [ˈluːnər] adj. 月球的；月亮的；阴历的
Sample Sentences：
The lunar stone is different from earth's.
The Spring Festival is the lunar New Year.
The 15th day of the eighth lunar month is the Mid-autumn Festival.
New Words：
traditional [trəˈdɪʃənl] adj. 传统的;习俗的
traditionally [trəˈdɪʃənəli] adv. 传统上;传统地
Sample Sentences：
It's traditional in America to eat turkey on Thanksgiving Day.
The traditional breakfast in this area includes bacon and eggs.
Traditionally, people clean the house before the Spring Festival.
Most Europeans traditionally celebrate Christmas Eve (December 24).
New Words：
lantern [ˈlæntərn] n. 灯笼
Lantern Festival n. 元宵节
Sample Sentences：
The night lantern glowed softly in the darkness.
The Lantern Festival is a traditional festival in China.
There is an ice lantern show in Harbin every year in winter.