A control volume is: （ ） A: An isolated system B: A closed system but heat and work can cross the boundary C: A specific amount of mass in space D: A fixed region in space where mass, heat and work can cross the boundary of that region

_________ is defined as a cognitive process in which the vehicle provides mental access to the target within the same domain; and in cognitive literature is modeled as Idealized Cognitive Models.? Metonymy|Mental space|Cross-space mapping|Metaphor

The children are always warned the street when the trafic light is red . a. not to cross b. to cross A: not to cross B: to cross

跨境电子商务的英文名称是（ ） A: Cross Border Commerce B: Cross border Trade C: Cross Border E-commerce D: Cross Border Communication

“cross this square”中“cross”的意思是

St. Andria Cross (The white cross on the blue background) represents _____________

St. George Cross (The red cross on the white background) represents___________.

Be careful when ______ the road. A: [A] crossing B: to cross C: cross

In the movie, Ellie said: ‘cross your heart.’ Here ‘ cross your heart ’ means ________.

There are millions of stars in______ A: space B: a space C: the space