_______, when Marx was already _______, he found it was important to study the situation in Russia, so he began to learn Russian.
| A．In 1870s, in his fifties | B．In 1870s, in fifties |
| C．In the 1870s, in fifties | D．In the 1870s, in his fifties |
She often goes to work __________ .
| A．by a underground | B．by underground | C．by the underground | D．take the underground |
There __________ a sports meeting in our school next week.
| A．won't have | B．isn't going to | C．won't be | D．isn't going to have |
—Bob, can you read the number 2, 307,018?
—Yes, I can. It’s ________.
| A．two million, three hundred and seven thousand, and eighteen |
| B．two million, and three hundred and seven thousand, and eighteen |
| C．two millions, three hundred and seven thousands, and eighteen |
| D．two millions, three hundred and seven thousands, eighteen |
This is ____ my pen. I’m writing with ___ pen.
| A．the , / | B．/, the | C．a, an | D．/, / |
---What should I do, doctor? ---_______healthy, you should take more exercise.
| A．Keep | B．To keep | C．Keeping | D．To keep away from |