79．Plastic is a kind of widely used m____.　　　　　　　　　 79．____

78．G____ speaking, the more expensive the TV is, the better it is.　 78．____

77．This v____ painting is worth more than a million.　　　　　 77．____

根据下列句子及所给汉语注释或首字母，在句子右边的横线上，写出空缺处各单词的正确形式。(每空只写一词)

76．My teacher always e____ me when I meet with difficulties. 　 76．____