When a third tone is followed by a first, second, fourth or neutral tone, the third tone should be pronounced as a low third tone. In other words it is a low sustained tone, as in jinzhang nervous and jief

1
Tone changes

• When a third tone is followed by a first,
  second, fourth or neutral tone, the third tone
  should be pronounced as a low third tone. In
  other words it is a low sustained tone, as in
  jinzhang nervous and jiefàng liberate.
  Both jin and jie stay in the lower part
  of your voice and you dont move the sound up.
  Lets practise the following phrases.

2
Tone changes

• faguan guanggào
• pindé xihuan
• huoche haibào
• qichuáng bijì
• tizhì haoxiàng
• xiaohái haixian

3
Tone changes

• zácao dadiànhuà
• zhizhang dàsaochú
• xixùn qízhema
• xiaoban jìnchukou
• kugua qidezao
• ménkou henhaokàn