I had difficulty walking back to my classroom.这句话是什么句型?请解释

I had difficulty walking back to my classroom.这句话是什么句型?请解释 请帮我翻译:I had just stared back for the house to change my clot 这是什么句型 he had great difficulty in ___(control) the car 解释下______Thinking back to the feeling that I had . I had to hold back tears as he left 这句话要怎么翻译? i had to hold back tears as he left 这句话有没有错? i was worried about my future.是什么句型结构?请解释为什么要用worried? I am back 是什么句型? I didn't go to bed until my father came back.came back可以用had My books are in the classroom,I am going to take back them 改 请翻译这句话Asks you to come back loves my again 这句英语有语病没?I feel the power back to my body.句型结构是怎样的?