普通麻花钻头修磨横刃的目地是为了把横刃磨短，使钻心处的前角减小，使钻头便于定位，减少轴向抗力，利于切削。
参考答案：错
用所给词的适当形式填空。
1. It was raining __________ (heavy), and we didn't go to school.
2. Mao Zedong was the __________ (found) of the PRC.
3. Our math teacher asked us __________ (not use) calculators.
4. The book is __________ (interesting) one of all the books.
5. Mike __________ (watch) TV yesterday evening.
“金蝉脱壳”这个成语，从生物学角度看，是指蝉在发育过程中存在的脱皮现象。
