问题
选择题
Ants are the most common life form on earth, ___________ tiny, their combined weight is greater than that of the combined weight of all humans.
A．though
B．although
C．even though
D．as if
答案
答案：A
考查连词：A. though虽然，可位于句首，句中，句末B. although虽然，只能在句首，C. even though即使，D. as if好像，句意：蚂蚁是地球上最常见的生命形式，虽然小，但它们团结的力量比人类团结的力量都大。选A。