To protect _______ hackers, security experts advise longer passwords _______ combinations of upper and lowercase letters, as well as numbers.

A. On choosing                                         

B. Having been chosen

C. Be chosen                                              

D. Having chosen

A. although          

B. and                  

C. however           

D. despite

A. have fought against                               

B. have prevented      

C. have suffered from

D. have avoided

A. passed             

B. wished            

C. touched           

D. moved

A. There was a great demand for the work of eighteenth-century artisans.

B. American sculptors were hampered by a lack of tools and materials.

C. Skilled sculptors did not exist in the US in the 1770’s.

D. Many foreign sculptors worked in the US after 1776.

A. Having a common centre                      

B. Having wavy centres

C. Having wavy movements                      

D. Having many centres

A. were hostile to each other                      

B. behaved well toward each other

C. hardly knew each other                         

D. were such close friends