【题目】 Experiments _______ that children can be instructed in swimming at a very early age, as early as about two months.

【题目】Yang Liwei is the 438th person _______ in space.

【题目】Because of the progress he ______ in his performance, he was soon promoted to project manager.

【题目】I walked in our garden, where Tom and Jim _______ a big sign onto one of the trees.

【题目】 The man was so surprised at _______ that he did not try to escape or defend himself.

【题目】She tapped me on _______ shoulder and teased me _______ my hair.

【题目】At our factory there are a few machines similar to _______ described in this magazine.

【题目】It is estimated that the number of tourists who travel abroad ______ in the past decade.

【题目】We bought them at ten dollars by ________.

【题目】Mary worked here as a _______ secretary and ended up getting a full-time job with the company.