______ life began on earth is one of the biggest puzzles that scientist found hard ______.
| A．How; solving | B．When; to be solved |
| C．How; to solve | D．Which; to solve |
Although John was the eldest in the family, he always let his sister _____ charge of the house.
| A．take | B．hold | C．make | D．get |
Dress warmly, _____ you'll catch cold.
| A．on the contrary | B．or rather | C．or else | D．in no way |
This book gives a brief _____ of the history of the castle and details of the art collection in the main hall.
| A．outline | B．reference | C．article | D．outlook |
How can we get this language point _____ to the students.
| A．down | B．round | C．across | D．into |
They have held several meetings to _____ next year's production plans.
| A．set down | B．make out | C．work up | D．draw up |