| 1. | It has a half-life of about 41/2 billion years .
它的半衰期大约为45亿年。 |
| 2. | They are of about the same strength .
他俩力气不相上下。 |
| 3. | The mine had yielded a total of about 3714 tons of coal .
这座矿已生产了3714吨煤。 |
| 4. | Seawater invades for a distance of about 50 miles upstream .
海水浸入上游远至50英里。 |
| 5. | He was a pert little blonde of about six years .
他是个唐突而漂亮的小孩，大约六岁左右。 |
| 6. | A man of about twenty-eight spent a summer in our village .
一个年约二十八岁的男子来我们村消夏。 |
| 7. | After the age of about thirty they abandon individual ambition .
他们一过三十就放弃了个人的雄心壮志。 |
| 8. | Geodetic theodolites generally have circles of about 140mm diameter .
大地经纬仪的度盘直径一般为140毫米。 |
| 9. | New channel are being dredged each year at a cost of about $74,000,000.
新航道每年的疏浚费用约为74,000,000美元。 |
| 10. | He was a man of about thirty, with a muscular throat and a large, mobile mouth .
他年约三十，喉头发达，嘴皮灵活。 |
