Shenzhou Ⅶ mission is a critical step in Project 921,

Shenzhou Ⅶ mission is a critical step in Project 921,
China's manned space program.The last time China had
sent a man in space was in 2005.It now plans to
build a space lab complex after two years.Shenzhou Ⅶ ,
the first Chinese space mission with full crew,which
seeks not only conduct the country's first spacewalk,
but also offers important technical points of reference
for future missions .By 2010,two unmanned aircrafts and
other manned spaceship with a crew of three will start work
on China's first space lab,completed the second phase of
the three stage Project 921.
英语改错,最后一行不用改,前面10行有9行都是错了一处的.求改.