题目

阅读下面短文，根据语境、音标或单词等提示，在每个空格内填入一个适当的单词，使短文意思完整、行文连贯。Handwriting has【1】 (become) a dying art. Now children start using keyboards as soon as they begin school. But writing things by hand may be an 【2】 /ɪmˈpɔːtnt/ way for us to train our brains.Writing by hand is different from typing. Typing means choosing the whole letter by 【3】(touch) a key.【4】, if we write by hand, we should use strokes (笔画) to make a letter. These finger actions make the large parts of the brain to work, 我炮兵阵地位于地面A处，两观察所分别位于地面点C和D处，已知DC=6000米，∠ACD=45°，∠ADC=75°，目标出现于地面点B处时，测得∠BCD=30°，∠BDC=15°（如图所示）．求炮兵阵地到目标的距离（结果保留根号）．