如果多项式﹣$\frac{1}{5}$abc+$\frac{1}{5}$ab²﹣a²bc的一个因式是﹣$\frac{1}{5}$ab，那么另一个因式是（　　）

一个正方形的周长是16厘米，面积是____平方厘米。

桌面上放有6张卡片（卡片除正面的颜色不同外，其余均相同），其中卡片正面的颜色3张是绿色，2张是红色，1张是黑色．现将这6张卡片洗匀后正面向下放在桌面上，从中随机抽取一张，抽出的卡片正面颜色是绿色的概率是（）

根据短文理解选择最佳答案。

    Let's Explore (探究) The Nature!

    Are you interested in animals and nature? Do you want to enjoy your summer holiday and learn something interesting and useful?

    Here comes your CHANCE! Youth Explore as prepared you with a THREE-DAY SUMMER PROGRAM! You can take part in many hands-on activities and meet with live animals, giraffes, pandas, tigers, and so on! Here's more information about the program：

    Age: Students aged 8~16

    Groups: There are 2 programs for you to choose from. Each program needs at most 15 students.

Program cost: $230 for members； $250 for non-members

  How to do: Simply come to our centre to get an application form (申请表). Send your completed form on or before 11^th July, 2014(Friday).

Notes:

①NO FREE LUNCHES ARE PROVIDED because of personal food differences. You may either bring a lunch-box or pay for lunch at our restaurants.

②Both programs will start 1 DAY later if there is a warning of rainstorms.

COME AND JOIN US NOW!! DON'T MISS THE CHANCE!!