下列运算正确的是（） A．2x+3y=5xy B．5m2•m3=5m5 C．（

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问题选择题

下列运算正确的是（　　）

A．2x+3y=5xy

B．5m²•m³=5m⁵

C．（a-b）²=a²-b²

D．m²•m³=m⁶

答案

A.2x+3y无法计算，故此选项错误；

B.5m²•m³=5m⁵，故此选项正确；

C．（a-b）²=a²-2ab+b²，故此选项错误；

D．m²•m³=m⁵，故此选项错误．

故选：B．

选择题

—You look unhappy . What’s wrong ?

—I find ____ difficult ______on well with my classmates

A．it; to get

B．it ; getting

C．that ; to get

D．that ; getting

翻译题

翻译以下短语并完成句子。

1) recognize... as

2) recognize sb. /sth. to be _

3) recognize that should+do_

4)I_____Peter by his appearance although I hadn't seen him for 10 years.虽然我有10年没见彼得了，但是我还是凭他的外貌认出了他。

5) Liu Xiang____one of the ten first- class athletes in the world．刘翔被认为是世界上十佳运动员之一。

6)______that environment pollution has become one of the most serious problems that people face. 人们一致认为环境污染已经成为人们面对的最严重的问题之一。