1选择题
Look at the ruler. It is 15 ________ long.
- A. millimetres
- B. centimetres
- C. metres
- D. kilometres
答案：B
解析：考查长度单位的选择。15对于毫米来说太大，对于米和千米来说太小，厘米是合适的单位。易错点是学生可能混淆单位换算，如将cm和m混淆。
2选择题
There are 24 hours in a day. What time is it when the clock shows 3 p.m.?
- A. 3 o'clock
- B. 13 o'clock
- C. 15 o'clock
- D. 21 o'clock
答案：C
解析：考查24时计时法。下午3时用24时表示是15时。易错点是学生可能直接选择3，忘记转换。
3填空题
A pencil is 18 cm long. A book is 2 times as long as the pencil. The book is ________ cm long.
答案：36
解析：考查“倍的认识”。2 times as long as 18 cm is 18 × 2 = 36 cm。易错点是学生可能误用加法。
4填空题
The perimeter of a square with a side length of 5 cm is ________ cm.
答案：20
解析：考查正方形周长公式。周长 = 边长 × 4 = 5 × 4 = 20 cm。易错点是学生可能忘记乘以4或计算错误。
5计算题
Calculate: 345 + 278 =
答案：623
解析：考查万以内的加法（进位）。计算时注意个位5+8=13，向十位进1；十位4+7+1=12，向百位进1；百位3+2+1=6。易错点是忘记加进位点或进位错误。
6计算题
Calculate: 802 - 356 =
答案：446
解析：考查万以内的减法（退位）。个位2减6不够，向十位借1，但十位是0，需连续向百位借1。百位8借1剩7，十位得10，再借1给个位剩9，个位12-6=6；十位9-5=4；百位7-3=4。易错点是连续退位时容易出错，如忘记退位点或计算错误。
7解答题
Tom has 12 apples. He gives 1/4 of them to his sister. How many apples does Tom give to his sister?
答案：Tom gives 3 apples to his sister. (12 ÷ 4 = 3)
解析：考查分数的初步认识（几分之一）。1/4 of 12 means 12 divided by 4, which equals 3. 易错点是学生可能误解分数的含义，直接用12减去4。
8解答题
A rectangular garden is 8 metres long and 3 metres wide. What is the perimeter of the garden?
答案：The perimeter is 22 metres. (Perimeter = (8 + 3) × 2 = 11 × 2 = 22)
解析：考查长方形周长公式。周长 = (长 + 宽) × 2 = (8 + 3) × 2 = 22米。易错点是学生可能只算长和宽的和，忘记乘以2，或者计算错误。