工程中研究不同问题时,可取不同的力学模型以简化计算。
A. 对
B. 错
1.Shehadnosoonersatdown______someonestartedknockingatthedoor
A. when
B. after
C. than
D. while
2.Oldercomputersarenotabletorunthesenewprograms,______causesthemtoperformmoreslowly.
A. that
B. which
C. what
D. where
3.Acompany______staffmembershaveagoodunderstandingofsuchsoftwarewillbeabletouseitmoreefficiently.
A. whose
B. that
C. who
D. whom