2. I ________ (write) letters since breakfast.
3. I ________ (write) 3 letters since breakfast.
4. Sorry, but Mr. Smith ________ (leave) for
5. I ________ (look) for him everywhere, where can he be?
2. I ________ (write) letters since breakfast.
3. I ________ (write) 3 letters since breakfast.
4. Sorry, but Mr. Smith ________ (leave) for
5. I ________ (look) for him everywhere, where can he be?
感叹词是用来表示说话时表达的喜怒哀乐等情感的词。它不构成后面句子的一个语法成分，却在意义上与它...
原因状语从句 [编辑本段]原因状语从句 一、引导原因状语从句的从属连词 主要的有because, as, since,f...
十四．过去将来完成时： would / should have + 过去分词 表示从过去某个时间看将来某时之前已经完成...
六．现在完成进行时： have / has + been + 现在分词 1．表示从过去某时开始发生，一直延续到现在且可...
四．过去进行时： were / was + 现在分词。 1．表示过去某一时刻或阶段正在发生的动作。 . I was play...
（一）名词变复数： 1．规则名词复数形式： 在单数名词后加s day days week weeks 2．在以 o, s, x, c...