the usual way of saying or writing ‘they would’ . This is not often used in formal writing （they would的通常说法或写法，正式书面语中不常用）
They said they’ d be happy to help. 他们说很乐意帮忙。
2
the usual way of saying or writing ‘they had’ when ‘had’ is an auxiliary verb . This is not often used in formal writing （had作助动词使用时they had的通常说法或写法，不常用于正式文体）
He knew they’ d met somewhere before. 他知道他们曾经在什么地方见过面。