Teaching aims
（教学目的）
Knowledge aims:
1. Get students to learn the useful new words and expressions in this part:
patent, courtyard, walnut, distinguish, merciful, product, powder, perfume, stainless, cube, abrupt, convenient, caution, expectation, passive, merry, seize, criterion, valid, file, ripe, string, glue, freezing, greengrocer, identification, directory, dial, rainfall, innocent, lantern, bear, jam, forehead, dynamic, dot, tap, wire, straw, current, helicopter, triangle, stable, associate, practical, refrigerator, court, extension, version, competence, jeep, personnel
call up, now and then, set about, in case, beaten track, dive into, set out (to do), hang on, get through, ring back, ring off
