Despite their______of interest, Fleming kept trying to develop chemical     ______ it would be safe and effective.

A．lack, so as to

B．lacking, so as to

C．lack, so that

D．lacking, so that

挤密桩地基包括()。

A、灰土桩地基

B、砂石桩地基

C、水泥粉煤灰碎石桩地基

D、夯实水泥土复合地基

E、粉煤灰地基