Every means______tried but without any result．

单项选择题As a salesman, he works on a (an) ______ basis, taking 10% of everything he sells.

单项选择题It is said that a grave of a middle aged man ______ about 2,300 BC was found by some English archaeologists in the year of 2002.

单项选择题I'll show my ______ to you as soon as they come out.

单项选择题It is essential that these application ______ forms back as early as possible.

单项选择题Dr. Smith was always ______ the poor and the sick, often providing them with free medical care.