The costs of materials for product B are made up as follows.Material P： $1，000Material Q： $600Material R： $1，025Material S： $375If the material proportions were displayed on a pie chart， how many degrees would material Q represent？（ ） A: 120 degrees B: 204 degrees C: 144 degrees D: 72 degrees

An opaque material is （） A: a material that can be seen through B: a translucent(半透明的) material C: a material that can not be seen through D: a lucent material

The cost of materials for product A are as follows. Material W: $2,250 Material X: $3,000 Material Y: $3,600 Material Z: $150 If the material proportions were displayed on a pie chart, how many degrees would material Y represent?

What is the process principle of welding A: laser radiation onto material B: melting of material C: resolidfying of material D: absorption of material

The functions of references are the follows except for:

Classification of rolling by product as follows

In a real network, it usually follows ______.

中国大学MOOC: The quantity of material in the material purchases budget is greater than the inferred from quantity of material in the material usage budget. Which of the following statements can be this situation?

(The more) kinetic (energy in) the particles of (a material), the (hottest) the material is.（） A: The more B: energy in C: a material D: hottest

The material flow can be divided into the following ( ) two categories according to whether the material flow is mainly caused by human activity A: Material biogeochemical flow and its anthropogenic flow B: Material flowing with the atmosphere and with the water body C: Material industrial and agricultural flows D: Material industry flow and consumption flow