stiff adj.①硬的，僵直的②（态度、举止）拘谨的，呆板的
The sturdy box was made of stiff cardboard.那个结实的盒子是用硬纸板做的。
John is shy and seems stiff,but if you get to know him, he is a lot of fun.约翰很腼腆，看起来有点呆板，但你跟他熟悉之后就会发现他非常有趣。
stimulate vt.剌激，激励，激发
The government plans to cut taxes in order to stimulate the economy.政府计划实施减税，以刺激经济。
sting v.刺；刺痛
She wore gloves when she was gardening to prevent the nettles from stinging her.她种植花木的时候会戴着手套，以避免被荨麻刺伤。
stock n.①库存②股票，股份
It is now halfway through winter and food stocks are already low.冬天才过去一半，食物库存量就已经很少了。
She buys and sells stocks and shares.她买卖股票和股份。
"Nobody is perfect" is Janet's husband's stock expression for whenever he makes a mistake. “人无完人”是珍妮特的丈夫每次犯错时都会说的话。
stoop v.弯腰，屈背
Bob stooped so he wouIdn't bump his head on the low eaves.鲍勃俯下身，这样才不会被低矮的屋檐撞到头。
strain n.①紧张；压力②血统；物种 vt.过滤
The strain of meeting a daily deadline made the columnist very anxious.每天都会遇到最后期限的压力，这让专栏作家非常紧张。
Scientists have discovered a new strain of virus which may be responsible for the disease.科学家们发现了一种新的病毒，它可能是造成这种病的罪魁祸首。
Janet strained the particles from the chemical solution.珍妮特从化学溶液中滤除微粒。
strap n.带，皮带
Could you help me fasten the strap around my suitcase?你能帮我系上手提箱上的皮带吗？
strategy n.策略，战略
The company will spend $6 million on the development of new products and sales strategy.公司将投人600万美元，用于开发新产品和制定销售策略。
strengthen vt.加强，巩固
The new constitution will further strengthen the powers of the president.新章程将进一步加强总裁的权力。
stress n.重压，压力 着重，强调；重读
Many heavy trucks put a lot of stress on the old bridge.许多辆軍型卡车给这座古老的大桥带来了许多压力。
She has repeatedly stressed that the laboratory's safety standards are the best in the country.她不断强调，实验室的安全标准在全国是最高的。