Scientists are trying to develop a special material, ________ they will make use of in spacecraft.
His daughter has __________ good knowledge of the English language and this will be an advantage over others in finding __________ proper job.
That tree, __________ are almost bare, is a very old one.
一 Would you mind my having a look at your new iPad? 一 ________.Please go ahead.
Susan advised me not to buy the vase, but I bought it _____.
Wearing dark glasses can _______ your eyes from the sun.