1选择题
Look at the picture. The ruler is about 15 ______ long.
答案：B
解析：本题考查长度单位的选择。图片通常显示一把常见的学生尺子，长度约为15厘米(cm)。学生易混淆毫米(mm)、分米(dm)和米(m)。15毫米太短，15分米(1.5米)太长，15米更不符合实际。
2选择题
Tom has 3 apples. Mary has 6 apples. Mary's apples are ______ Tom's.
- A. two times as many as
- B. three times as many as
- C. four times as many as
- D. five times as many as
答案：A
解析：本题考查“倍”的概念。Mary有6个苹果，Tom有3个，6是3的2倍，所以是two times as many as。学生需理解倍数的表达方式。
3填空题
It's 3:00 p.m. in the 12-hour clock. In the 24-hour clock, it's ______.
答案：15:00
解析：本题考查24时计时法。下午3时需要加上12小时，即3+12=15时。学生易忘记加12，直接写成3:00。
4填空题
A schoolbag weighs 3 ______. A pencil weighs 5 ______.
答案：kg; g
解析：本题考查质量单位的选择。书包较重，通常用千克(kg)；铅笔较轻，通常用克(g)。学生易混淆千克和克的使用场景。
5计算题
Calculate: 456 + 278 = ?
答案：734
解析：本题考查万以内加法（进位）。计算时需注意个位6+8=14，向十位进1；十位5+7+1=13，向百位进1；百位4+2+1=7。学生易忘记进位或进位计算错误。
6计算题
Calculate: 803 - 457 = ?
答案：346
解析：本题考查万以内减法（退位）。计算时需注意个位3减7不够，向十位借1，但十位是0，需连续借位。学生易在连续退位时出错，忘记在退位点标记或计算错误。
7解答题
A rectangular field is 8 meters long and 5 meters wide. What is its perimeter?
答案：The perimeter is (8 + 5) × 2 = 13 × 2 = 26 meters.
解析：本题考查长方形周长公式。周长 = (长 + 宽) × 2。学生易忘记乘以2，或者将长宽相加后直接作为答案。注意单位要统一，题目已给出米，答案也需带单位。
8解答题
A pizza is cut into 8 equal slices. Tom eats 3 slices. What fraction of the pizza did Tom eat?
答案：Tom ate 3/8 of the pizza.
解析：本题考查分数的初步认识。将整体（一个披萨）平均分成8份，取其中的3份，即八分之三。学生易将分子分母写反，或误写成3/5等错误分数。