5. You’d better go to Fuzhou by train. (改为否定句)You _____ _____ _____ _____ to Fuzhou by train.

You don't would better go to Fuzhou by train

You would not better go to Fuzhou by train.
因为只题为将来时态，所以you'd是you would的缩写，改为否定只要在would后加not就行了。如果只有三个空的话would not可以缩写为wouldn't

这个 'd 是had的缩写.这是一个特殊的句型.had better (not) do sth 最好(别)做某事.所以改否定句是
You had better not go to Fuzhou by train

You had better not go to Fuzhou by train.
had better do sth 最好做某事

You would not go to Fu Zhou by train
you'd better=you woule better变否定句直接在would前加not