Here are the exercises for practising the verb 'be' in the PRESENT TENSE

1. TO BE (present tense) – exercises
http://www.ego4u.com/en/cram-up/grammar/simple-
present/form/exercises?06
http://www.learnenglishfeelgood.com/english-verbs-tobe1.html
http://www.englishmaven.org/HP6/To_Be_Exercise1.htm
http://www.englishmaven.org/HP6/To_Be_Exercise2.htm
http://www.englishmaven.org/HP6/To_Be_Exercise3.htm
http://www.englishmaven.org/HP6/To_Be_Exercise4.htm
http://examenglish.com/grammar/be.htm
pdfs
http://www.englishforeveryone.org/PDFs/To_Be_Exercise_1.pdf
http://www.englishforeveryone.org/PDFs/To_Be_Exercise_2.pdf
http://www.englishforeveryone.org/PDFs/To_Be_Exercise_3.pdf
http://www.ebpai.com/storage/ejercicios%20verb%20to%20be%201
.pdf (instructions in Spanish)