envelope是什么意思

双语用例

• I folded the letter in half and put it in an envelope.

• Send a self-addressed envelope for our free catalogue.

• An envelope was waiting for me when I got home.

• Do you recognize the writing on the envelope?

• The teacher opened the sealed envelope containing the exam papers.

• The pump and seed envelopes are shown multiplied by 10 for clarity.

• Initial data collection tools, together with the random allocation, were packaged within sealed, opaque envelopes, each bearing a sequential trial number.

• Stationary instrumental groups are placed around the audience and successively play sounds of the same pitch and timbre with similar dynamic envelopes (crescendo-decrescendo).