【单选题】

Excitement, fatigue, and anxiety can all be detected from someone’s blinks, according to psychologist John Stern (21) Washington University in St. Louis. Stern specialized in the study on these tiny twitches, using them as sensitive (22) of how the brain works. "I use blinks as a psychological measure to make (23) about thinking because I have very little (24) in what you tell me about what you are thinking." He says. "If I ask you the question, ’what does the phrase a rolling stone gathers no moss mean ’ you can’t tell me (25) you’ve started looking for the answer.But I can, by watching your eyes."

Blinks also tell Stern when you have understood his question--often long before he’s finished asking it--and when you’ve found an answer or part of (26) . "We blink at times (27) are psychologically important." He says. "You have listened to a question, you understand it, (28) you can take time out for a blink.Blinks are (29) marks. Their timing is tied to what is going on in your (30) ."
Stern has found that (31) suppress blinks when they are absorbing or anticipating (32) but not when they’re reciting it. People blink later, for example, (33) they have to memorize six numbers instead of two. "You don’t blink," he says, "until you have (34) the information to some short-term memory store."And if subjects are cued (35) the set of numbers is coming, say, five seconds, they’ll curb their blinks until the task is (36) . Similarly, the more important the information that people are taking in, the more likely they are to put their blinks on hold for (37) Pilots blink less when they’re (38) for flying a plane than when they (39) their eyes from the road to the rearview mirror.But if they see the flashing lights of a state trooper behind them, their (40) will move fast to the speed-meter and back to the mirror.
A、that B、whatC、where
D、why