僕はまだ彼女の住所を思い出せない。

。

I still can't remember her address.

Literal

I [topic-は] still her [possessive-の] address [object-を] cannot-recall.

思い出せない — potential negative of 思い出す ('to recall, remember'). まだ ('still') indicates the failure to remember persists. 住所 (じゅうしょ, 'address').