J.J.Garrett所提出的打造优秀用户体验的五要素分别是战略层、（）、结构层、（）和（）。

Different stages and types of stars are mentioned in Reading Passage 1. Choose ONE of the types or stages (A-H) from the box below which best matches the descriptions (Questions 1-6).
Write your answers in boxes 1-6 on your Answer Sheet.
NOTE: you may use any answer more than once.
A．nebula
B．main sequence star
C．red giant
D．white dwarf
E．black dwarf
F．supernova
G．neutron star
H．black hole
the Sun ______