Which of the following statements are TRUR and which are FALSE? Why? （要解释原因） a. All normal children have equal ability in learning their first language. b. It is easy for parents to teach their children grammar. c. The young child is not taught to speak, or to understand his language. There is no formal learning of grammar or pronunciation practice. d. At first children do not inflect nouns or verbs. e. Children learn their native language well whenever they start and whatever kinds of language samples they receive. f. For a child to acquire his mother tongue the most basic requirement is that he hears people speaking this language. He will then begin to learn the language. g. Phonology and grammar are finite, tightly structures systems, the child must master them before puberty in order to be a native speaker of the language.