Ответ: a
The plane (leaves)in half an hour but Nick (is not) at the airport yet. b
My best friend (loves) science
fiction films but they (do not interest) me. c I (do not
study) chemistry because it
(is) difficult. d I (do not
dance) because I
(look) stupid. e The Sun (does not go) round the Earth, the
Earth (goes) round the Sun! f
My new computer (does) lots
more things than my old one, and it (does not 
crash) g My dad (does not have) any qualifications but
he (has) got a really good
job. h Fire (needs) oxygen
to burn. It (does not burn)
without oxygen. i My teacher (does not own) a mobile phone because
some people think they
(are) bad for your health.  j
According to scientists, animals
(live) longer if they (do not eat)  too much.