Are these words very difficult ________ (remember)?

Are these words very difficult ________ (remember)? It's very difficult-----(remember)these new english words.ca these words and sentences are difficult. It's difficult ------(remember)these words.Look!The children These words and sentences are difficult.what other words did Some new words in this lesson are difficult()(remember). these words and sentences are difficult什么意思 The child isn't able to remember these difficult words,_____ These Words are all very important.（ ）t ________ dictionaries are very popular with students these d please （ ）（remember）these news words because they are too us These words and sentences are difficult的意思拜托各位大神