阅读理解。 This  is  a picture of Mr  Li's  family.  The man in the middle is Mr Li,  the father.  The woman is the mother. They have two sons. The son behind Mr Li is Li Lei. He's thirteen. The son in the front of Mrs Li is Li Ming. He's eleven. Li Lei and Li Ming are in the same school, but not in the same grade. Li Lei is in Grade Two. Li Ming is in Grade One. They are good students. 1. There are _______ people in the picture. A. three B. four C. five D. six 2. Mr Li is ________ Li Lei. A. in front of B. behind C. on D. under 3. Mr and Mrs Li have ___________. A. one boy and one girl B. two boys C. two girls D. one boy 4. Li Ming is _______ brother. A. We don't know. B. Mrs Li's C. Li Lei's D. Mr Li's 5. How old are Li Lei and Li Ming? They are_________. A. 11 and 13 B. 11 and 12 C. 12 and 11 D. 13 and 11