Adverbs commonly modify verbs, adjectives, and other adverbs, but they can sometimes modify other parts of speech such as conjunction.
Adverbs can modify subordinating conjunctions, mostly to show proximity of time (1-9) between two situations, like in these examples:
(Modifying adverbs underlined and modified conjunctions in blue font)
1. The projector malfunctioned right when the presentation started.
2. Just when the clock struck midnight, the fireworks lit up the sky.
3. Just as soon as he heard the news, he called his parents to inform them.
4. Immediately after the meeting ended, the team gathered to discuss their next steps.
5. Almost immediately after he sat down, the phone rang. [An adverb phrase, which contains an adverb (almost) modifying another adverb (immediately), modifies conjunction here.]
6. Not long after the ceremony concluded, the guests began to leave.
7. Shortly before the concert started, the venue was packed with people.
8. Just before the sun rose, the sky was painted with beautiful colors.
9. Just as the rain started to pour, we ran for cover.
10. He has been feeling much better ever since he started exercising daily.
11. She got soaked in the rain on her way home simply because she had forgotten her umbrella.
12. She volunteered at the local shelter every weekend just because she loved animals.
Learn more: Adverbs can modify almost every part of speech – and even some phrases. Learn what else can adverbs modify.