1. They are going to discuss the downsides **of** our business. When we talk about the negative aspects of something, we use the preposition "of" to indicate what the downsides are related to. 2. We can use this tool **for** many purposes. When we talk about the ways in which something can be used, we use the preposition "for" to show the purpose or function. 3. Who will share the responsibility **with** me? When talking about sharing or dividing responsibility, we use the preposition "with" to indicate who will be involved in the responsibility-sharing. 4. These strategies complement **each other** and form a profitable combination. When two or more things complement each other, we use the phrase "each other" to indicate the mutual beneficial relationship. 5. The Managing Director gave a high evaluation **of** this partnership. When evaluating something, we use the preposition "of" to show what is being evaluated. 6. The manager included some important data **in** his sales report. When talking about including information in a document or report, we use the preposition "in" to indicate where the information is placed. 7. He has just become the owner **of** the company. When someone acquires ownership of something, we use the preposition "of" to show what is being owned. 8. Did he manage to meet **the** deadline? When referring to a specific deadline that has been previously mentioned or is known, we use the article "the" before the word "deadline" to indicate a specific point in time that the person needed to meet.