以來

In a sentence

• 自从去年以来，我一直在学习中文。

  Since last year, I have been learning Chinese.

  Here, '以来' is used with '自从' to indicate the time period from last year up to now.

• 干旱以来，农作物的产量一直在下降。

  Since the drought, crop yields have been declining.

  In this sentence, '以来' follows a specific event ('干旱') to mark the time since that event occurred.

• 加入俱乐部以来，我认识了很多新朋友。

  Since joining the club, I have made many new friends.

  Here, '以来' connects a personal event ('加入俱乐部') with the current or ongoing situation, emphasizing the time span.