未知题型
用所给单词的正确形式填空 The purpose of new technology is to make life (easy) _______ , not to make it more difficult.
easier
单项选择题 China has ______ most famous types of embroidery, each with its own style and different themes.
单项选择题 按90°接线的相间功率方向继电器，当线路发生正向故障时，若φK为30°，为使继电器动作最灵敏，其内角仗值应是__（）
问答题 1、平行投影法分为哪两种？
