N2 — outside your level filter

それとも

それともsoretomoN2neutral

or — puts a second alternative to the listener, between two questions

コーヒーにする?それとも、紅茶こうちゃがいい?

koohii ni suru? soretomo, koucha ga ii?

Shall we make it coffee? Or would you rather have tea? casual

打うち合あわせは今日きょうでしたっけ。それとも、明日あしたでしたっけ。

uchiawase wa kyou deshita kke. soretomo, ashita deshita kke.

Was the meeting today? Or was it tomorrow? neutral

All examples3

or — offers the listener a second choice, usually the last one

  1. コーヒーにする?それとも、紅茶こうちゃがいい?

    koohii ni suru? soretomo, koucha ga ii?

    Shall we make it coffee? Or would you rather have tea? casual

  2. 打うち合あわせは今日きょうでしたっけ。それとも、明日あしたでしたっけ。

    uchiawase wa kyou deshita kke. soretomo, ashita deshita kke.

    Was the meeting today? Or was it tomorrow? neutral

  3. 会場かいじょうでお受うけ取とりになりますか。それとも、ご自宅じたくまでお送おくりいたしましょうか。

    kaijou de ouketori ni narimasu ka. soretomo, go jitaku made ookuri itashimashou ka.

    Would you like to collect it at the venue? Or shall we send it to your home? formal

How it's formed1

Notes

What follows それとも is interrogative; what precedes it may be an offer or a
proposal instead (コーヒーを入いれるよ。それとも、紅茶こうちゃがいい?).
A flat declarative list of options takes または or もしくは.