あい

ごご ３じに えき で あい ましょう。

The correct answer is "あい". This is the verb stem of "あいます" (to meet). To make a suggestion or invite someone, Japanese uses the volitional form, which is created by attaching "ましょう" to the verb stem. Therefore, "あいましょう" correctly means "Let's meet," forming a polite invitation in the sentence. The verb stem is the core part that remains when removing the -masu ending.

正解(せいかい)は「あい」です。動詞(どうし)「あいます」の語幹(ごかん)です。「～ましょう」と組(く)み合(あ)わせて「あいましょう」（会(あ)いましょう）という誘(さそ)いの形(かたち)になります。