One can make a password safer by ______.
A. inserting pictures between numbers
B. avoiding the use of letters altogether
C. setting up a firewall against computer hackers
D. using complicated combinations of numbers and letters
The study of modem creatures ______.
A. is unrelated to the study of extinct animals
B. finds evidence missing in the study of extinct animals
C. has findings similar to those of the study of extinct animals
D. reveals a different pattern from the study of extinct animals
According to the passage, red-list animals are more likely to ______.
A. be lazy
B. be timid
C. live long
D. sleep less
在碳素钢的焊接过程中，只能从单面焊接的纵向和环向焊缝，其内壁最大错边量不应超过()。
A. 4 mm
B. 3 mm
C. 2 mm
D. 1 mm
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