Choose the correct option.

1. The Arabic numeral system ___ in India.
A. is thought to have evolved
B. is thought to evolve

2. The term 'mathematics' ___ by Pythagoras.
A. is known to have been invented
B. has been known to be invented

3. ___ that the idea of 'numbers' evolved gradually over time.
A. There's thought
B. It is thought

4. It ___ that mathematics contains the answer to all questions.
A. could argue
B. could be argued

5. ___ early civilizations developed different ways of writing down numbers.
A. It has known that
B. We know that

6. Ancient Egyptians are considered ___ to the development of mathematics.
A. to contribute
B. to have contributed

7. Greek mathematics ___ with Thales of Miletus.
A. is thought to have begun
B. has been thought to begin

8. ___ both these theories are true. 
A. We may believe
B. It has believed that 

9. They weren't ___ in this case.
A. thought to be involved
B. thinking to have been involved

10. You are ___ for your exams in the summer.
A. expecting to have studied
B. expected to be studying