The boy walk about in order to keep warm .（改為同義句）
The boy walk around in order to keep warm
There used to be low and dirty houses.(改為反義疑問(wèn)句,didn't there）
Parents should allow teenagers to choose their own clothes .（改為含情態(tài)動(dòng)詞的被動(dòng)語(yǔ)態(tài)）
teenagers should be allowed to choose their own clothes by parents
I don not know which mobil phone I should choose.（改為簡(jiǎn)單句）
I don not know which mobil phone to choose
In 1519 a traveler went to American from Europe .He discovered the tomato .（合并為含定語(yǔ)從句的復(fù)合句）
In 1519 a traveler went to American from Europe where he discovered the tomato.
I have been to Hong Kong __where___ _cars____ _go____ on the left.（同上）
保護(hù)環(huán)境是我們每個(gè)人的責(zé)任.It is __our___ ___duty__ _to___ ___protect__ the environment.
今天我離開(kāi)家的時(shí)候衛(wèi)生間的燈亮著.Tihs morning I left home __with__ ___the _ ___bathroom_ ___light_ __on__.IF someone takes away her books whitout her permission， she will ) him。（be angry with ；be in agreement with）when you leave the room ，don not forget to （ ） thelights。（turn off ：look……down）IF someone takes away her books whitout her permission， she will （be angry with ) him。（be angry with ；be in agreement with）when you leave the room ，don not forget to （ turn off ） thelights。（turn off ：look……down