根据汉语提示写单词。 1. I______ ______ be afraid of the dark. 2. Sometimes he was______ (缺席) from classes. 3. It was______ (准确地) what I needed. 4. It was__________(幸运的) that we didn’t have to carry him. 5. Li Wen is a______ (正常的) 15-year-old boy from the countryside. 答案:1. used to 2. absent 3. exactly 4. fortunate/lucky 5. normal如图所示是一个拴在完全遵循胡克定律的弹簧上的木块,台面水平光滑,点O是平衡位置,木块受到的弹力随x的变化图象用下图中哪个表示最恰当 ( )