So difficult it to work out the problem that I decided to ask Tom for advice．
A．I did find B．I have found C．did I find D．have I found
The rescue workers were working around the clock, ________ supplies to Yushu Qinghai Province after the earthquake．
A．to send B．sending C．having sent D．to have sent
After the earthquake, the first thing the local government did was to provide for the homeless families．
A．accommodation B．occupation C．equipment D．furniture．
________ this cake, you'll need 2 eggs, 175 g sugar and 175 g flour．
A．Having made B．Make C．To make D．Making
Although the causes of cancer ________, we do not yet have any practical way to prevent it．
A．have uncovered B．have been uncovering
C．are uncovering D．are being uncovered
Someone who lacks staying power and perseverance is unlikely to _________ a good researcher．
A．make B．turn C．get D．grow
