关于空间分辨力的影响因素，下列叙述正确的是（） A.声波频率越高，纵向分辨力越差 B

一位同学向量筒中倒入一定量液体后，他用仰视方法计数，读出的体积是20mL，则该液体可能是（　　）

A．20mL

B．20.5mL

C．19.8mL

D．以上都不对

下面四种施工成本管理的措施中，( )是其他三类措施的前提和保障。

A．组织措施

B．技术措施

C．经济措施

D．合同措施

化学反应都遵守质量守恒定律，请根据质量守恒定律的相关知识完成下列问题：

(1)下列各项中，在化学反应前后一定不变的是____________(填数字序号)。

①元素的种类 ②物质的种类 ③原子的种类 ④分子的种类 ⑤原子的数目 ⑥分子的数目

(2)应用质量守恒定律配平化学方程式：

(3)实验室常用下图所示实验验证质量守恒定律。

四位同学设计了如下A、B、C、D四个实验，并按下图实验操作来验证质量守恒定律，实验中观察到B、C实验前后天平依然保持平衡，某同学认为B、C实验都能验证质量守恒定律，你认为他的说法________(填“是”或“否”)正确；而A、D实验天平不平衡，其中D实验天平不平衡的原因是_____________。

瘀斑（）

A．皮下出血直径＜2mm

B．皮下出血直径3～5cm

C．皮下出血直径＞5cm

D．片状出血伴有皮肤显著隆起

E．片状出血伴有皮下握雪感

Skin Care

护肤

The eyes are described as the windows of the soul, the mouth as the courier of thought, and the nose as the servant of olfaction. The skin is just the frame to the picture. Unfortunately, many judge themselves according to this frame. They could either have feelings of content or censure of their own physical features. Good health and self-esteem go hand-in-hand during the process of exercising and establishing good health habits. The skin’s clarity of ache, wrinkles, and sunburns is merely assistance to their stature of confidence. Having healthy skin is a step to confidence. Becoming worry-free of appearances is practicing good sleeping, eating, and drinking habits that lead to the success of a healthy looking person. Adolescents need about 8-10 hours of sleep a night, and adults need less than that. However, the body needs to rest and save energy for ongoing activities. Eating properly from the four basic food groups maintains the balance of proteins and nutrients. Fluid consumption of water is more recommended by doctors than the choice of soft drinks that are out on the market. Water provides plenty of water that is the key to have that fresh natural look. When actress, Rebecca Gayheart, (the commercial model of Noxema)was interviewed by Shape magazine in the 1998 November issue, she said, "My beauty routine is basically plenty of sleep and lots of water. " Exercising regularly will circulate blood and keep skin firm and toned. Getting involved in an activity that a person enjoys, and they are most likely to be happy and look more healthy. Having to be the largest organ of the human body, the skin’s main function is to protect the body from microbes. Because of the large coverage of the skin over the body, it would be encouraged to take care of its texture and form. Many desire healthy looking skin that is smooth and firm. The attraction for this desire makes the market place booming with industry in order to fulfil the consumers’ desire. Viewers at home can be guaranteed to see some type of commercial advertisement on TV that focuses on the integument and appendages of hair, make-up, lotions, or nail products. Keeping the face clear promotes good self-esteem and confidence to one’s appearance. Good skin can save time from make-up. When a girl wants to step out for a night of the town, the pimples and blemishes on her face will be the last thing that she will be conscious of. Little things can be erupted from something so miniscule. The first thing to combat would be the pores. Pores are what allows the skin to breathe. If pores were to be blocked by dirt, oil, or make-up, unwanted ache would take place. Avoid wearing make-up to sleep and touching the face when hands are dirty. Pores can be kept clean if washed daily, by using a soft facial cleanser versus the usage of deodorant soaps. Whenever heading for the pool or a day out in the sun, never forget to protect your skin from hazardous Ultraviolet (UV)rays. By overexposure to Ultraviolet rays, you’re more likely to develop cancer. Through the appliance of sunscreen upon the exposed skin, and underneath make-up we can decrease the odds are more likely to be in your favor. Do not go out and tan, because that ruins the outer membranes. The high percentage of risk upon skin cancer is a large fear.

It could be inferred that people apply sunscreen upon the exposed skin when outdoors because they want to().

A. be healthy looking

B. protect the pores of the skin

C. become more sun-tanned

D. reduce the possibility of skin cancer