Sửa lỗi:
1. (In the) sixteenth century, (it was thought) that a compass needle (pointed) north (because) some mysterious influence of the star
2. (During) lava cools (exceptionally) fast, (it forms) a natural glass (called) obsidian
3. (Since) it’s acute sense of (smell), (the) blood-hound is often (used in) tracking
4. Art critics (do not all) agree on what (are the qualities) that (make) a painting (great)
5. A test pilot (tries out) new (kinds of ) aircraft (to determine ) if (are they safe)
6. Opine Bernards are (too) good at (following) the scent of humans, even in snow, that they (are used) by ski. Paltrow’s (as) rescue dogs
7. (Desiring) to leave their own marks of identify inside the White House, most presidents wives (redecorate) at least some portion of (its) room (as soon as arrival) there
8. The prices of accommodation (are) (as) big that many people (cannot) afford to (buy) a house