Many things now cost double what did a year ago.请问这里的what起什么作用

Many things now cost double what did a year ago.请问这里的what起什么作用 请问Many things now cost double what they did a year ago这个句子的结构和语法是怎么回事?这里cost的用法,还有为什么用what they did Nowadays you can buy many things on___in many big suoermakets.选项:a、creditb、 cardc、 calld、 cost but many things that can't be seen now many things 求助mamy things now cost double what they did a year ago 句子中词的成份,句子结构 Many things seemed ( ) a hundreds years ago,but now they've all come true (6/6) means.For now I do know it means so many things. (6/6) means.For now I do know it means so many things. nothing can beat me,now seem to me is impossibe.many things also can beat me. 翻译many things. still many things是什么意思 请问many things是什么意思 many intersting things (t ) some things cost more than you realise They buy sports equiprment,go to sporting ______ and do many things that cost money.A.cash B.show C.people D.event I will remember what you have said .Many things have not forever but I only wane now. Luckily,with the development of China,many things have ______ ,and children can get a goodeducation now.