`16.` After David had gone home, we arrived.
`17.` I haven't worn that dress for three weeks.
- The last time + S + V2/V-ed + ... + was + time + ago
`->` S + haven't/hasn't + VpII + ... + for + time
`18.` After Jack had left the office, I arrived there.
`19.` While I was having dinner, the phone rang.
- While + S + was/were + V-ing + ...,S+ V2/V-ed + ...
`20.` The last time I was to the cinema was 2 months ago.
- The last time + S + V2/V-ed + ... + was + time + ago
`->` S + haven't/hasn't + VpII + ... + for + time
`21.` I have never visited Janpan before.
- This is the first time + S + V2/V-ed + ...
`->` S + haven't/hasn't (have/has never) + VpII + ... + before
