Beginning with software version 4-0-0.rel，how many virtual routers canbe configured on the ERX Edge Router？（）

What rules are the OSI following when they certify products as open source？

A.The software being distributed must be redistributed to anyone else without any restriction.

B.The software force vendors to work on that much harder to hold their market share in the face of viable open source alternatives by competing with proprietary software products.

C.The source code must be made available.

D.The license can require improved versions of the software to carry a different name or version from the original software.

At the beginning of a thank-you letter, you should express appreciation for their help and support.()

The step-test was given ______.

A．at the beginning and at the end of the 7-week period

B．after each exercise period

C．only at the beginning of the 7-week period

D．only at the end of the 7-week period

A.at the beginning

B.at the end

C.in the middle

D.at both the beginning and the end

3D printing is just at the beginning stage. It is not ____.

A、mature

B、ripe

C、grown

A.开始

B.蝴蝶

C.感动

D.回复

A.Since the beginning

B.have become

C.in

D.the way how

A.is scheduled to begin

B.is scheduled to beginning

C.schedules to begin

D.schedules to beginning