49. These exercises / too difficult / students / do / without / mistakes.
A. These exercises are too difficult for students doing without mistakes.
B. These exercises are too difficult for students to do without mistakes.
C. These exercises are too difficult with students to do without mistakes.
D. These exercises are too difficult with students doing without mistakes.
50. If / Bob/have / lot / money/he/buy/car/ and /travel/ round / world.
A. If Bob has a lot of money, he would buy a car and travel round the world.
3. If Bob had a lot of money, he will buy a car and travel round the world.
C. If Bob had a lot of money, he would buy a car and travel round the world.
D. If Bob had a lot of money, he bought a car and travel round the world.