Acerca de "A practical english grammar exercises 1"
Contents: Preface: Exercise 1.-Auxiliary Verbs, present tense 2.-Auxiliary Verbs, past tense 3.-Auxiliary Verbs in short answers 4.-The simple present tense 5.-The simple present tense, Negative and Interrogative 6.-The present continuous tense 7.-The simple present and the present continuous 8.-The simple present and the present continuous 9.-The simple past tense (mainly irregular verbs) 10.-The simple past tense, Negative and Interrogative 11.-The past continuous tense 12.-The simple past and the past continuous 13.-The simple past and the past continuous 14.-The present perfect tense 15.-The present perfect and the simple past 16.-The present perfect and the simple past 17.-The present perfect and the simple past 18.-The present perfect continuous tense 19.-The present perfect and the present perfec continuous 20.-"For" and "Since".