Qian Xuesen tried many times _________ he found the solution to the puzzle about space technology.
#31596
A
after
B
before
C
since
D
when
推荐题目
_________ we have been classmates for three years, she hasn’t left me much impression, so I can’t remember her after graduation.
#30157
A
Since
B
Although
C
Because
D
Unless
．We are taught that a business letter should be written in a formal style ____ in a personal one．
#34803
A
less than
B
other than
C
better than
D
rather than
These natural parks are important for preserving animals, which would ________ risk dying out.
#31895
A
merely
B
rather
C
otherwise
D
moreover