~たとたんに (the instant)

The instant she stepped into her room, she burst into tears.

The instant she was alone, she opened the letter.

The instant she heard the news, she suddenly burst into tears.

I knew it was her the moment I saw her.

The moment I saw her, I thought it was her.

The candle went out the moment the wind blew in.

The moment she stepped into her room, she started crying.

The moment she saw me, she burst into laughter.

I recognized Mary the moment I saw her.