英语翻译A certain communication system is made up of 40 symbols.A maximum of two symbols placed together,order not mattering,make up a word.What is the maximum number of words in this communication system?

英语翻译重点：past a certain point 英语翻译a dedicated building on certain days. a certain 英语翻译A,inspired B,certain C,calm D,satisfied 英语翻译in a certain store where they sell puddings. 英语翻译用certain造句 英语翻译certain experiences just missed a certain date certain a certain什么意思 in a certain way act in a certain in a certain sense 英语翻译being a problem gives you a certain identity这两句话开头都是什么用法 英语翻译it's a certain person that posts that many selfies.calm down honayyy 英语翻译certain about A 确信 B 保护 C 当然 D 保证 英语翻译such an experience befell a certain young girl the first time she was travelling alone. 英语翻译‘water’ is stuff that bears a certain similarity relation to the water around here. certain