彼女はその手紙を読んで

she read the letter and

→ 彼女
phrase Rare #36,583
she read the letter and This is an incomplete phrase ending in the て-form of 読む (to read). It connects to what happens next and can mean “reading the letter,” “after reading the letter,” or “while reading the letter,” depending on the following words.
JA: 彼女はその手紙を読んで、泣き始めた。
EN: She read the letter and started crying.

実は彼女はその手紙を読んでさえいなかったのです

In fact, she hadn't even read the letter.

彼女はその手紙を読んでいたとき悲しそうな顔だった

She looked sad when she was reading the letter.

彼女はその手紙を読んで悲しそうだった

She looked sad after reading the letter.