臺灣籍旅美老師今天交給我們的句子是：

Researchers think that ground sloths could have been pushed out by an oncoming ice age, or competition with other species, maybe humans, who arrived in the region around the time most of the sloths went extinct. Some of the smaller sloths did survive and migrated to the treetops.
學者認為地懶之所以被淘汰，可能是因為冰河時期的來臨，或是跟其他的物種競爭所致，這物種很可能是人類。人類到達樹懶生存區域的時期，剛好和樹懶絕種的時期吻合。有些小型的地懶確實存活了下來，而且移居到樹上去了。

學習重點：

1.sloth 樹懶
sloth (n.) 樹懶

2.species 物種
species (n.) 物種

3.arrive 到達
arrive (v.) 到達
arrival (n.) 到達

4.region 地區
region (n.) 地區

5.extinct 絕種的
extinct (adj.) 絕種的
extinction (n.) 滅絕

6.migrate 遷移
migrate (v.) 遷移
migration (n.) 遷移
immigrate (v.) 遷移、移民
immigration (n.) 移居