第1组：
1.He could speak English. (He could speak 可以构成一套主谓系统,一般过去时态)
2. He would like to speak English. (He would like to speak 可以构成一套主谓系统,一般现在时态)
3.Keep learning English, please. (Keep动词原形开头可以构成祈使句。)
4. He keeps learning English every day. (He keeps 可以构成一套主谓系统,一般现在时态)
