In William Shakespeare’s play Romeo and Juliet, Friar Laurence contributes to the tragic ending by:

- Giving Romeo a sleeping potion
- Telling no one of his advice to Juliet
- Going to Mantua himself to speak to Romeo
- Pretending to be Lord Capulet

The correct options are:

- Giving Romeo a sleeping potion
- Telling no one of his advice to Juliet

In William Shakespeare’s play Romeo and Juliet, Friar Laurence contributes to the tragic ending by:

1. Giving Romeo a sleeping potion - Friar Laurence plays a pivotal role in the tragic end by giving Romeo a sleeping potion. In Act 4, Scene 1, Friar Laurence gives Juliet a vial containing a potion that will make her appear dead temporarily. His intention is for her to fake her own death so that she can escape her arranged marriage to Paris and be with Romeo. However, this plan sets off a chain of events that ultimately leads to the deaths of Romeo and Juliet.

2. Telling no one of his advice to Juliet - After giving Juliet the sleeping potion, Friar Laurence instructs her to take it the night before her wedding. However, he fails to inform anyone else about his plan, including Juliet's parents and Romeo. This lack of communication contributes to the misunderstandings and confusion that unfold in the play, ultimately leading to tragedy.

3. Going to Mantua himself to speak to Romeo - Friar Laurence also contributes to the tragic ending by deciding to send a letter to Romeo, explaining Juliet's plan and asking him to come back to Verona. However, he also decides to personally go to Mantua to deliver the message. Unfortunately, due to a series of unforeseen events and delays, the letter does not reach Romeo in time, causing him to believe that Juliet is truly dead.

4. Pretending to be Lord Capulet - Friar Laurence does not pretend to be Lord Capulet in the play. This action is not part of his character or actions contributing to the tragic ending of Romeo and Juliet.

It is important to note that while Friar Laurence's intentions were initially good, his actions and decisions ultimately contribute to the tragic ending of Romeo and Juliet.