Ответ:
Краткое пояснение: Преобразуем активное предложение в пассивное, начиная с "It".
It is generally thought that life won't be found on Mars.
Ответ: It is generally thought that life won't be found on Mars
It is generally thought that life won't be found on Mars.
Ответ: It is generally thought that life won't be found on Mars