N-COUNT A switch is a small control for an electrical device which you use to turn the device on or off. 开关例：
Leona put some detergent into the dishwasher, shut the door, and pressed the switch.
N-PLURAL On a railway track, the switches are the levers and rails at a place where two tracks join or separate. The switches enable a train to move from one track to another. 转辙器
V-T/V-I If you switch to something different, for example to a different system, task, or subject of conversation, you change to it from what you were doing or saying before. 转向例：
Estonia is switching to a market economy.
The law would encourage companies to switch from coal to cleaner fuels.
N-COUNT Switch is also a noun. 转变例：
The spokesman implicitly condemned the United States policy switch.
PHRASAL VERB Switch over means the same as . 转变例：
Within a few years the whole country will switch over to digital television.
V-T/V-I If you switch your attention from one thing to another or if your attention switches, you stop paying attention to the first thing and start paying attention to the second. 转移 (注意力)例：
My mother’s interest had switched to my health.
V-T If you switch two things, you replace one with the other. 调换例：
In half an hour, they’d switched the tags on every cable.
Handheld mode 手提模式
ADJ A handheld device such as a camera or a computer is small and light enough to be used while you are holding it. 手持式的; 掌上的例：
…a handheld electric mixer.
N-COUNTHandheld is also a noun. 手持式装置例：
Users will be able to use their handhelds to look up timetables on the net, search for a local hotel, and check their bank accounts.
seamlessly，无缝地。seam => n. 缝；接缝 vt. 缝合；接合；使留下伤痕。
N-VAR Transition is the process in which something changes from one state to another. 转型例：
The transition from a dictatorship to a multi-party democracy is proving to be difficult.
V-I If someone transitions from one state or activity to another, they move gradually from one to the other. (逐渐地) 转向例：
Most of the discussion was on what needed to be done now as we transitioned from the security issues to the challenging economic issues.
strap /stræp/ CET4 TEM4
N-COUNT A strap is a narrow piece of leather, cloth, or other material. Straps are used to carry things, fasten things together, or to hold a piece of clothing in place. 带子例：
Nancy gripped the strap of her beach bag.
She pulled the strap of her nightgown onto her shoulder.
V-T If you strap something somewhere, you fasten it there with a strap. 用带子绑例：
She strapped the baby seat into the car.
switch vt. 转换；用鞭子等抽打
transition n. 过渡；转变；[分子生物] 转换；变调；
wrist strap 腕带；