Though Mandela﹙曼德拉﹚____27 years in prison﹙监狱﹚, he thought it meaningful.
| A．planned | B．spent | C．happened | D．waited |
Please stand ______ rows.
| A．in | B．on | C．at | D．with |
Boys, help _______ to the delicious food.
| A．yourself | B．himself | C．yourselves | D．you |
—What are the flowers _______?—They are beautiful.
| A．look | B．like | C．look like | D．likes |
______ she did this, all would be well.
| A．As long as | B．So long | C．As if | D．Even if |
_______ the heavy rain, many people were late for work.
Because B. Because of C. As D.Since