لك

In a sentence

• هذا الكتاب لك.

  This book is for you.

  Here, 'لك' is used to indicate possession or allocation to someone—'for you.'

• يمكنني أن أشرح لك هذا الأمر.

  I can explain this matter to you.

  In this sentence, 'لك' is used as an indirect object to indicate the person to whom something is directed—'to you.'

• لدينا مفاجأة خاصة لك.

  We have a special surprise for you.

  Here, 'لك' conveys the idea of being intended for someone—'for you.'