difficult to加什么词?

difficult to加什么词? difficult前加什么冠词 much difficult than前面加什么is? difficult是加动词ing?还是加to do sth. Very difficult to understand什么意思 Difficult to It can difficult to know happen为什么要在can后加be,be有什么用 the operation,which lasted for over four hours,proved to be very difficult.请问prove to be是词组还是什么,不加to be行不行 Mary found _______,A.Chinese difficult to learn B.Chinese difficult to be learnedMary found _______A.Chinese difficult to learnB.Chinese difficult to be learned选A的话，Chinese 和difficult 之间不用加is she fing it difficult to stop smoking .find要不要加S?除了单三 名词和动词还有什么情况要加s? Mary found_____.AChinese difficult to learn BChinese difficult to be learned选什么,要解析 英语中形容词后加不定式可以做什么句子成分比如下面这句做的是什么成分?Daming found their accents really difficult to understand.可否改写成 Daming found it really difficult to understand their accents. be difficult后加什么?比如：It will be difficult （ ）the team to win the next World Cup.A at B for C on D with选什么?为什么? prove difficult 和 prove to be difficult 有什么区别?The operation proved to be difficult.Rescue operations are proving difficult. to后加什么词 to后面加什么词 请问有be difficult to do sth 这个词组吗?be difficult XXXXX 还有什么词组? The search proved difficult和The search proved to be difficult有什么区别?