In the following options，（ ）are standard parts.
A: Commonly used thread fasteners
B: Keys
C: Gears
D: Springs
A: Commonly used thread fasteners
B: Keys
C: Gears
D: Springs
举一反三
- BioBricks are standard biological parts. Like the standard parts in other industries, Biobricks can be connected with each other, or they can be disassembled and reassembled with other parts.
- Which of the following statements are the benefits of a commonly used language?
- Which of the following italicized parts is used as an object?_____ (2011)
- All of the following are meaningful and commonly used except______.( ) A: off-white B: gas-mask C: after-thought D: pocket-pick
- Which of the following options does not belong to the commonly used random sampling method () A: typical sampling B: multi-stage sampling C: Stratified sampling D: Systematic sampling E: Cluster sampling