Final answer:
The given sentences can be converted to direct speech as follows: "Martha warned Toby that nobody would know who broke the window unless somebody spoke up." "Tim said, 'I'll go start the car,' and left because someone tried to start a fight with his friend."
Step-by-step explanation:
Direct: Martha warned Toby that nobody would know who broke the window unless somebody spoke up.
Direct: Tim said, "I'll go start the car," and left because someone tried to start a fight with his friend.
Learn more about Direct and Indirect Speech