according to national standard, which of the following are preferred scales?
which of the following heights are provided in national standards?
the symbol "gb/t 14689-2008" denotes that the concern national standard is compulsory.
when we make a drawing, a frame should be drawn inside of the outmost edges of the drawing sheet. there are two styles of drawing sheet layout: with a filling margin and without a filling margin.
which of the following lines are used as dimension lines, extension lines, leader lines, construction lines, section lines and projection lines?
which of the following are the projection rules of the projections of points？
what are the projection properties of frontal line?
if a line is an oblique line, the projections of the line will be foreshortened lines in the three planes of projections.
the connecting line between the spacial point and its horizontal projection reflects the distance of the point to the horizontal plane of projection, and it equals the coordinate x of the point.
according to the difference of x coordinates of the two points, we can tell the relative position of these two points in front-rear direction.
which of the solid can we make lines on its surfaces?
when we need to make a point on the surface of a solid, on which of the following solid the auxiliary latitude circle method can be used?
when making projections of points in the conical surfaces of cones and spherical surfaces on spheres, auxiliary element method and auxiliary latitude circle method can both be used.
when a sphere is cut by a plane at any location, all of the projections of the produced intersection are circles.
when dimensioning a composite solid which is formed by cutting, the dimensions should be given at the location where the solid is cut.
when the views of a composite solid formed by adding are drawn, the solid can be considered as formed by all features, and then the views of the features are drawn one by one. in the process of drawing views of the features, we should keep in mind that the composite solid is a whole solid.
which of the usages of center lines in views are correct?
the isometric projection of a frontal circle is an ellipse. the minor axis of the ellipse is in coincidence with , and the major axis of the ellipse is perpendicular to .
the isometric projection of a profile circle is an ellipse. the minor axis of the ellipse is in coincidence with , and the major axis of the ellipse is perpendicular to .
what representation methods are included in the method "view",that is, non-sectioned view?
choose the properties of the general section line from the following description.
in occasions of representing a relatively complex part, three standard views are not enough to show all the details of the part clearly and completely.
which screw thread term is the nominal diameter?
which options belong to the five important screw thread elements?
in the following options, are standard parts.
which option is the type symbol for pipe threads?
which surfaces are the working surfaces of the key joints?
in dimension φ60f7 in a detail drawing, φ60 is , f is , 7 is .
which of the follow numbers are of ra values?
when a shaft is represented, the axis of it should be placed horizontally.
tolerance is the difference between the permitted minimum and maximum sizes of a part. it also equals the difference between the upper limit deviation and the lower limit deviation.
what of the following are the contents of assembly drawings?
what of the following are indicated in assembly drawings?
what of the following are included in parts lists of assembly drawings?
what of the following are of the special representation methods of assembly drawing?
the methods which can be used in representing machine parts, include regular views, sectional views, removed sections, and the like, which can also be used to represent assemblies.
in using autocad software, the operation sequence of which of the following commands is start the command, select the objects, specify base point, specify second point.
in using autocad software, the following descriptions are about the usages of the command trim, which of the are correct?
in using autocad software, when we draw a rectangle, we should give two points in the rectangle. which of the following description is correct about the two points?
in using autocad software, when the command mirror is used, the mirror line must be center lines.