根据人体合成情况,20种氨基酸分为()和()两大类。
蛋白质多肽链中的肽键是指一个氨基酸的()和另一个氨基酸的()脱水缩合连接而形成的。
主动语态原句:William repairs cars in his garage.一般现在时:The cars ___________1____________ by William in his garage.现在进行时:The cars ___________2____________ by William in his garage.现在完成时:The cars ___________3____________ by William in his garage.
主动语态原句:Wild fires destroy many forests.一般现在时:Many forests ________1_________ by wild fires.现在进行时:Many forests ________2_________ by wild fires.过去完成时:Many forests ________3_________ by wild fires.