why are dictionaries useful?郁闷,周末作业真多,有些英语单词搞不懂!大哥哥大姐姐帮帮忙!

these are dictionaries提问dictionaries These are dictionaries.对dictionaries提问 Dictionaries are ...1.Dictionaries are not allowed to use when you are taking an exam.还是 2.Dictionaries are not allowed to be used when you are taking an exam.哪句对?Thanks .Please tell me why. why are dictionaries useful?郁闷,周末作业真多,有些英语单词搞不懂!大哥哥大姐姐帮帮忙! Dictionaries are ____(help) to our study. Dictionaries are very ( )use to our study how dictionaries are made语法现象.详细~ how much are the dictionaries?同义句 Are those dictionaries here 改为单数是? Those are my dictionaries同义句 How dictionaries are made?How are dictionaries made?这两个哪个是对的? some dictionaries are in english some are in chinese是什么意思 There are some dictionaries in these bags?(单数形式) their dictionaries are (in the classroom)对括号部分提问 These dictionaries are mine.（一般疑问句 否定回答） 求开头是“Dictionaries are very useful的原文 ________ dictionaries are very popular with students these days. They are some good dictionaries.改为单数句怎么改